Do adolescent trajectories of riding with an impaired driver and driving impaired predict similar behaviors in early adulthood?

BACKGROUND: A recent study shows four trajectories of riding with an impaired driver (RWI) and driving while impaired (DWI) from adolescence to emerging adulthood. We examined prospective associations of adolescent RWI/DWI trajectory class with early adulthood RWI/DWI behavior. METHODS: Data were from the NEXT Generation Health Study (NEXT), a nationally representative longitudinal study (N = 2783) beginning with a 10th-grade cohort completing 7 annual assessment waves (W1-W7) between 2010 and 2016 and a later follow-up mixed methods study. Four RWI and DWI trajectories derived from a recently published latent class analysis study (RWI (last 12 months); DWI (last 30 days) dichotomized as ≥ once vs. none) were used: Abstainer, Escalator, Decliner, and Persister. In the follow-up examination, a purposive subsample (N = 105, 26.3 ± 0.5 y/o, Female 50.5%) of NEXT participants were selected by trajectory (31 Abstainers, 33 Escalators, 14 Decliners, and 27 Persisters) for in-depth interviews 4 years after NEXT. In interviews, self-reported RWI events (number of times) related to alcohol (Alc-RWI) or marijuana (MJ-RWI) use in the last 12 months, and DWI events (number of times) related to alcohol (Alc-DWI) & marijuana (MJ-DWI) use in January 2020 (pre-COVID pandemic) were collected using structured surveys. General linear models were used to examine associations of adolescents' RWI/DWI trajectories with early adulthood RWI/DWI behavior, controlling for sex, health status, education attainment, and work hours. RESULTS: The mean number (SD) of Alc-RWI and MJ-RWI events reported by Escalators (3.83(2.48), 2.43(2.77)) and Persisters (3.83(2.43), 3.57(2.54)) were higher (p≤0.05) than Abstainers (0.82(1.42), 0.77(2.04)) and Decliners (1.81 (2.69), 1.38 (2.04)). Similarly, Escalators (1.61 (2.28), 1.88(2.69)) and Persisters (1.96(2.08), 1.93(2.48)) reported more Alc-DWI and MJ-DWI events than Abstainers (0.18 (0.53), 0.42(1.38)) and Decliners (0.00 (0.00), 0.08(0.28)). Linear regression models indicated membership in Escalator and Persister classes compared to Abstainer class was associated (p≤0.01) with higher engagement in RWI/DWI in early adulthood. CONCLUSION: Adolescents with escalating and persistent high RWI/DWI may continue these health risking behaviors into their mid-twenties. Decliners during the transition maintained low RWI/DWI into their mid-twenties. Taken together, these findings suggest that earlier reduction may have long-term effects. Our findings can be used to inform the precision tailoring of prevention efforts aimed at effectively reducing alcohol/drug impairment crash injuries and related deaths among those in early adulthood.

Teen drivers' awareness of vehicle instrumentation in naturalistic research.

INTRODUCTION: Naturalistic driving methods require the installation of instruments and cameras in vehicles to record driving behavior. A critical, yet unexamined issue in naturalistic driving research is the extent to which the vehicle instruments and cameras used for naturalistic methods change human behavior. We sought to describe the degree to which teenage participants' self-reported awareness of vehicle instrumentation changes over time, and whether that awareness was associated with driving behaviors. METHOD: Forty-two newly-licensed teenage drivers participated in an 18-month naturalistic driving study. Data on driving behaviors including crash/near-crashes and elevated gravitational force (g-force) events rates were collected over the study period. At the end of the study, participants were asked to rate the extent to which they were aware of instruments in the vehicle at four time points. They were also asked to describe their own and their passengers' perceptions of the instrumentation in the vehicle during an in-depth interview. The number of critical event button presses was used as a secondary measure of camera awareness. The association between self-reported awareness of the instrumentation and objectively measured driving behaviors was tested using correlations and linear mixed models. RESULTS: Most participants' reported that their awareness of vehicle instrumentation declined across the duration of the 18-month study. Their awareness increased in response to their passengers' concerns about the cameras or if they were involved in a crash. The number of the critical event button presses was initially high and declined rapidly. There was no correlation between driver's awareness of instrumentation and their crash and near-crash rate or elevated g-force events rate. CONCLUSION: Awareness was not associated with crash and near-crash rates or elevated g-force event rates, consistent with having no effect on this measure of driving performance. PRACTICAL APPLICATIONS: Naturalistic driving studies are likely to yield valid measurements of driving behavior.

Power of Food Scale in association with weight outcomes and dieting in a nationally representative cohort of U.S. young adults.

Food reward sensitivity may influence susceptibility to overeating in a permissive food environment, contributing to unintended weight gain and intentional weight loss behavior. This study examined associations of food reward sensitivity, assessed by the Power of Food Scale (PFS), with weight outcomes and dieting in a nationally representative cohort of U.S. emerging adults. Wave 5 (W5, 5th year of follow-up) respondents from the NEXT Generation Health Study were included (N = 2202, W5 age = 20.3 ± 0.02 years). Baseline and W5 BMI, W5 weight status (normal weight = 18.5 ≤ BMI < 25, overweight = 25 ≤ BMI < 30, obese = BMI ≥ 30), BMI change (W5-baseline BMI) and onset of overweight or obesity (OWOB) were calculated from self-reported height and weight. PFS (aggregate and 3 domain scores: food available, present, and tasted) and dieting for weight-loss were assessed at W5. Adjusted linear regressions estimated associations of PFS with W5 BMI and BMI change. Log-binomial regressions estimated associations of high W5 BMI (≥25), OWOB onset and dieting with PFS. Post hoc analyses estimated associations of PFS with W5 perceived weight status (overweight vs. about right or underweight). W5 BMI = 25.73 ± 0.32 kg/m(2), and OWOB onset occurred in 27.7% of participants. The PFS-food available score was associated with BMI change, ß ± SE = 0.41 ± 0.19. Other PFS scores were not associated with weight outcomes. Dieting prevalence was higher in participants with high versus low W5 BMI (61% versus 32%), and was positively associated with all PFS scores except the PFS-food tasted score, e.g., relative risk (RR) of dieting for PFS-aggregate = 1.13, 95%CI [1.01-1.26]. Post-hoc analyses indicated perceived overweight was positively associated with PFS-food available, 1.12, [1.01-1.24], and PFS-food present, 1.13, [1.03-1.24]. PFS was positively related to dieting and perceived overweight, but not concurrent or change in weight status in a representative cohort of U.S. emerging adults.

Validation of a contemporary adherence measure for children with Type 1 diabetes: the Diabetes Management Questionnaire.

AIMS: To evaluate the psychometric properties of the Diabetes Management Questionnaire, a brief, self-report measure of adherence to contemporary diabetes management for young people with Type 1 diabetes and their caregivers. METHODS: A total of 273 parent-child dyads completed parallel versions of the Diabetes Management Questionnaire. Eligible children (aged 8-18 years) had Type 1 diabetes for ≥1 year. A multidisciplinary team designed the Diabetes Management Questionnaire as a brief, self-administered measure of adherence to Type 1 diabetes management over the preceding month; higher scores reflect greater adherence. Psychometrics were evaluated for the entire sample and according to age of the child. RESULTS: The children (49% female) had a mean ± sd (range) age 13.3 ± 2.9 (8-18) years and their mean ± sd HbA1c was 71 ± 15 mmol/mol (8.6 ± 1.4%). Internal consistency was good for parents (α = 0.83) and children (α = 0.79). Test-retest reliability was excellent for parents (intraclass correlation coefficient =0.83) and good for children (intraclass correlation coefficient = 0.65). Parent and child scores had moderate agreement (intraclass correlation coefficient = 0.54). Diabetes Management Questionnaire scores were inversely associated with HbA1c (parents: r = -0.41, P < 0.0001; children: r = -0.27, P < 0.0001). Psychometrics were stronger in the children aged ≥13 years compared with those aged < 13 years, but were acceptable in both age groups. Mean ± sd Diabetes Management Questionnaire scores were higher among children who were receiving insulin pump therapy (n = 181) than in children receiving multiple daily injections (n = 92) according to parent (75.9 ± 11.8 vs. 70.5 ± 15.5; P = 0.004) and child report (72.2 ± 12.1 vs. 67.6 ± 13.9; P = 0.006). CONCLUSIONS: The Diabetes Management Questionnaire is a brief, valid self-report measure of adherence to contemporary diabetes self-management for people aged 8-18 years who are receiving either multiple daily injections or insulin pump therapy.

Associations of family meal frequency with family meal habits and meal preparation characteristics among families of youth with type 1 diabetes.

BACKGROUND: While benefits of family mealtimes, such as improved dietary quality and increased family communication, have been well-documented in the general population, less is known about family meal habits that contribute to more frequent family meals in youth with type 1 diabetes. METHODS: This cross-sectional study surveyed 282 youth ages 8-18 years with type 1 diabetes and their parents on measures regarding diabetes-related and dietary behaviours. T-tests determined significant differences in youth's diet quality, adherence to diabetes management and glycaemic control between those with and without regular family meals (defined as ≥ 5 meals per week). Logistic regression analyses determined unadjusted and adjusted associations of age, socio-demographics, family meal habits, and family meal preparation characteristics with regular family meals. RESULTS: 57% of parents reported having regular family meals. Families with regular family meals had significantly better diet quality as measured by the Healthy Eating Index (P < 0.05) and the NRF9.3 (P < 0.01), and adherence to diabetes management (P < 0.001); the difference in glycaemic control approached statistical significance (P = 0.06). Priority placed on, pleasant atmosphere and greater structure around family meals were each associated with regular family meals (P < 0.05). Meals prepared at home were positively associated with regular family meals, while convenience and fast foods were negatively associated (P < 0.05). Families in which at least one parent worked part-time or stayed at home were significantly more likely to have regular family meals than families in which both parents worked full-time (P < 0.05). In the multivariate logistic regression model, greater parental priority given to family mealtimes (P < 0.001) and more home-prepared meals (P < 0.001) predicted occurrence of regular family meals; adjusting for parent work status and other family meal habits. CONCLUSIONS: Strategies for promoting families meals should not only highlight the benefits of family meals, but also facilitate parents' skills for and barriers to home-prepared meals.

Associations of food preferences and household food availability with dietary intake and quality in youth with type 1 diabetes.

The objective of this study was to examine associations of food preferences and availability with dietary intake in youth with type 1 diabetes, for whom dietary intake and quality are essential to disease management. Youth (n=252, age 13.2±2.8 y, diabetes duration 6.3±3.4 y) reported preferences and parents reported household availability for 61 food items categorized as fruit, vegetables, whole grains, refined grains and fats/sweets. Youth energy-adjusted daily servings of food groups, Healthy Eating Index-2005 and Nutrient Rich Foods 9.3 scores were calculated from 3-day diet records. Associations of dietary intake and quality variables with preference and availability of all food groups were evaluated by linear regressions adjusted for sociodemographic characteristics. Fruit and whole grain intake were positively related to corresponding preference and availability; whole grain intake and refined grain availability were inversely related. Vegetable, refined grain and fats/sweets intake were unrelated to preference and availability. Diet quality measures were related positively to fruit preference and whole grain availability and inversely to refined grains availability. Findings indicate associations of dietary intake with food preference and availability vary by food group in youth with type 1 diabetes. Measures of overall dietary quality were more consistently associated with food group availability than preferences.

Cigarette smoking status and recurrent subjective health complaints among US school-aged adolescents.

BACKGROUND: Subjective health complaints are common among adolescents. There is evidence that girls are more likely to register complaints than boys. This study examines gender differences in the relationship between daily smoking and recurrent subjective health complaints in school-aged adolescents in the USA. METHODS: A cross-sectional design with a multistage probability sample was used to survey 13,339 middle and high school students (grades 6 through 10) with the US 2001-2002 Health Behavior in School-Aged Children Survey. RESULTS: Recurrent subjective health complaints were higher for adolescents who smoke daily and experiment with cigarettes than for those who never smoke. In logistic regression analyses, the odds of daily smoking increased twofold for both boys and girls who report recurrent irritability/bad temper. For girls, the odds of daily smoking were higher among those who reported recurrent headache, stomachache and backache compared with never smokers. For boys only recurrent backache and feeling dizzy were associated with increased odds of daily smoking. CONCLUSIONS: The relationship between recurrent subjective health complaints and daily smoking provides new insights into both conditions for school-aged adolescents. Findings from this study suggest different patterns of association between daily smoking and recurrent subjective health complaints occur for girls and boys. Further studies are needed to explore causes and treatment of daily smoking and recurrent health complaints among school-aged children.

Responsive parenting is associated with improved type 1 diabetes-related quality of life.

BACKGROUND: Improved quality of life is an important treatment goal for children and adolescents with type 1 diabetes. While previous research supports a relationship between family environment and quality of life, little research has addressed the relationship of parenting style constructs to quality of life in children with chronic disease. The present investigation assesses the relationship of parent responsiveness and demandingness with diabetes-related quality of life among children and adolescents with type 1 diabetes. METHODS: Baseline and 12-month follow-up self-report assessments were collected on a sample of 81 children with type 1 diabetes participating in an efficacy trial of a behavioural intervention to enhance adherence. The sample had a mean age of 13.3 years (SD=1.7) and duration of diabetes of 7.7 years (SD=3.7). Multiple regression analyses were conducted to determine the relationship of parent responsiveness and demandingness to diabetes-related quality of life at each time point. RESULTS: After adjusting for demographic and diabetes characteristics, as well as diabetes-specific parent-child behaviours, parent responsiveness was significantly associated with baseline diabetes-related quality of life (beta=0.23; P=0.04). This relationship was sustained at 12-month follow-up (beta=0.22; P=0.04) after adjusting for baseline quality of life and treatment group assignment, suggesting that parent responsiveness is associated with improved quality of life. CONCLUSIONS: Findings indicate the importance of a supportive and emotionally warm parenting style in promoting improved quality of life for children with type 1 diabetes. Appropriate parenting skills should be an element of diabetes family management health care.

Effects of ultra-wideband electromagnetic pulses on pre-neoplastic mammary epithelial cell proliferation.

Electromagnetic ultra-wideband pulses (UWB) or nanopulses, are generated by a wide range of electronic devices used in communications and radar technology. However, the specific effects of nanopulse exposure on cell growth and function have not been extensively investigated. Here, studies have been conducted to determine the effects of prolonged exposure to non-ionizing, low to moderate intensity nanopulses on the growth of pre-neoplastic CL-S1 mammary epithelial cells in vitro. Cells were grown in culture and maintained in serum-free defined medium containing 10 ng/ml EGF and 10 microg/ml insulin as comitogens. Studies showed that 0.25-3.0 h exposure to nanopulses of 18 kV/m field intensity, 1 kHz repetition rate and 10 ns pulse width had no effect on CL-S1 cell growth or viability during the subsequent 72-h culture period. However, exposure to similar nanopulses for prolonged periods of time (4-6 h) resulted in a significant increase in cell proliferation, as compared to untreated controls. Additional studies showed that nanopulse exposure enhanced CL-S1 cell growth when cells were maintained in media containing only EGF, but had no effect on cells maintained in defined media that were mitogen-free or containing only insulin. Studies also showed that the growth-promoting effects of nanopulse exposure were associated with a relatively large increase in intracellular levels of phospho-MEK1 (active) and phospho-ERK1/2 (active) in these cells. These findings demonstrate that prolonged exposure to moderate levels of UWB enhanced EGF-dependent mitogenesis, and that this growth-promoting effect appears to be mediated by enhanced activation of the mitogen-activated protein kinase (MAPK) signalling pathway in pre-neoplastic CL-S1 mammary epithelial cells.

Induced mitogenic activity in AML-12 mouse hepatocytes exposed to low-dose ultra-wideband electromagnetic radiation.

Ultra-wideband (UWB) technology has increased with the use of various civilian and military applications. In the present study, we hypothesized that low-dose UWB electromagnetic radiation (UWBR) could elicit a mitogenic effect in AML-12 mouse hepatocytes, in vitro. To test this hypothesis, we exposed AML-12 mouse hepatocytes, to UWBR in a specially constructed gigahertz transverse electromagnetic mode (GTEM) cell. Cells were exposed to UWBR for 2 h at a temperature of 23 degrees C, a pulse width of 10 ns, a repetition rate of 1 kHz, and field strength of 5-20 kV/m. UWB pulses were triggered by an external pulse generator for UWBR exposure but were not triggered for the sham exposure. We performed an MTT Assay to assess cell viability for UWBR-treated and sham-exposed hepatocytes. Data from viability studies indicated a time-related increase in hepatocytes at time intervals from 8-24 h post exposure. UWBR exerted a statistically significant (p < 0.05) dose-dependent response in cell viability in both serum-treated and serum free medium (SFM) -treated hepatocytes. Western blot analysis of hepatocyte lysates demonstrated that cyclin A protein was induced in hepatocytes, suggesting that increased MTT activity after UWBR exposure was due to cell proliferation. This study indicates that UWBR has a mitogenic effect on AML-12 mouse hepatocytes and implicates a possible role for UWBR in hepatocarcinoma.

Symptoms of depression in the oldest old: a longitudinal study.

This study examined depressive symptoms in a population-based, longitudinal sample of people aged 80 and older to determine initial prevalence of depressive symptoms and changes over time. Depressive symptomatology was assessed with the Center for Epidemiologic Studies-Depression scale (CES-D). The sample was drawn from the OCTO-Twin study, which examined 702 Swedish twins over age 80 in which both members of the pair were still surviving. For the present study, one member of each twin pair was randomly selected, resulting in a sample of 351. A comprehensive biobehavioral assessment was conducted at three time points over 4 years. Depressive symptoms were initially relatively low and decreased significantly between Wave 1 and Wave 2. At Wave 3, depressive symptoms increased slightly but not significantly. Participants who received a dementia diagnosis at some point in the study did not differ significantly on initial CES-D scores when compared to those participants who never received such a diagnosis. Lack of well-being, as opposed to negative affect, was the biggest contributor to the overall depression score at each of the three waves of measurement. Predictors of negative affect for this sample included activities of daily living, subjective health, and performance on the cognitive test, block design. None of these predictors were significant for lack of well-being.

Peer and parent influences on smoking and drinking among early adolescents.

Social influences can promote or discourage adolescent substance use. The authors surveyed 4,263 sixth- to eighth-grade students to assess the effect of peer and parent influences on adolescent substance use. The authors conducted separate multiple logistic regression analyses for smoking and drinking, controlling for grade, sex, and race. Positive independent associations with smoking and drinking were found for direct peer pressure and associating with problem-behaving friends. Independent negative associations with smoking and drinking were also found for parent involvement, parent expectations, and parent regard. In an analysis of interactions, peer pressure was positively associated with drinking for girls but not for boys and problem-behaving friends was positively associated with drinking for both boys and girls. The findings are consistent with the hypothesis that associating with deviant peers promotes and that authoritative parenting protects against smoking and drinking.

Associations between parent awareness, monitoring, enforcement and adolescent involvement with alcohol.

In a statewide random telephone survey of 454 parents and their 14- to 19-year-old adolescents, we examined the associations between various parenting strategies and self-reported teen drinking. Less teen drinking was associated with parents' reports of checking to see if other parents would be present at teen parties, particularly among White parents. Parents' monitoring of teens' activities was associated with feelings of competence at doing so. There was, however, no difference in drinking between teens with parents who did or did not report restricting their teens due to teen misbehavior. These findings suggest that a proactive parental monitoring approach may be associated with less adolescent drinking. Prospective research is needed to clarify the causal relationship between parental monitoring, efficacy and teen alcohol-related behavior.

Student-school bonding and adolescent problem behavior.

Adolescent problem behavior, including substance use, school misconduct and delinquency, is a national concern. Implicit in the concept of middle school is the recognition that students who develop positive social bonds with their school are more likely to perform well academically, and refrain from misconduct and other antisocial behavior. However, little scientific attention has been given to the complex interactions between middle school students and the school environment. Prior to implementing a middle school problem behavior prevention program we conducted a survey in the seven middle schools in one US school district. Out of 4668 grade 6-8 students enrolled, 4263 (91.3%) completed the survey. Student-school bonding was positively correlated with school adjustment (r = 0.49) and perceived school climate (r = 0.77), but inversely correlated with problem behavior (r = -0.39 to -0.43). Problem behavior was significantly higher (P < 0.001) among males than females and among students in higher grades. Conversely, school bonding, climate and adjustment were significantly higher (P < 0.001) among females than males, but declined significantly from one grade to the next. The data support the conclusion that school bonding is associated with problem behavior. We describe the development of a multiple-component intervention in middle schools designed to increase student-school bonding and prevent problem behavior.

Expectancies and other psychosocial factors associated with alcohol use among early adolescent boys and girls.

Early experimentation with drinking increases the lifetime risk for substance abuse and other serious health and social problems. We studied factors associated with early alcohol experimentation by surveying 4,263 sixth- to eighth-grade students (67.1% White, 23.5% Black, 7.2% other races combined; 2.2% missing data) from seven schools in one suburban school district. The prevalence of drinking in the last 30 days was 12.1% for boys and 13.1% for girls (12.6% overall); 6.6% among sixth graders, 11.1% among seventh graders, and 19.5% among eighth graders. In multiple logistic regression analyses, controlling for grade, positive alcohol expectancies, perceived prevalence, and deviance acceptance were associated positively, self-control negatively, with drinking for both boys and girls. Among boys, grade point average was negatively associated with drinking. Among girls, propensity for risk-taking and problem-behaving friends were positively associated and high parental expectations were negatively associated with drinking. Alcohol use in our sample of early adolescent boys and girls was better explained by modifiable psychosocial factors such as alcohol expectancies, perceived prevalence, and self-control than by grade.

Psychosocial, school, and parent factors associated with recent smoking among early-adolescent boys and girls.

BACKGROUND: Experimentation with smoking often begins during adolescence, but an adequate understanding of the factors associated with early initiation remains elusive. METHODS: Sixth- to eighth-grade students (n = 4,263, 67.1% white, 23.5% black, 7.2% other) from seven middle schools were surveyed. RESULTS: The overall prevalence of recent smoking (past 30 days) of 10.4% was similar for boys and girls and by race, but increased from 3.7% in sixth to 17.8% in eighth grade. In multiple logistic regression analyses positive outcome expectations, high perceived prevalence, deviance acceptance, and trouble at school were independently associated with smoking for both boys and girls. Among boys, problem-behaving friends, peer pressure, authoritative parenting, and mother's education and among girls, self-control problems, knowledgeable parents, and grade were independently associated with smoking. CONCLUSIONS: This is one of the few studies to report an independent association between smoking and outcome expectations, the first study to report an independent effect for peer influences among boys only, and one of several to find a negative association between smoking and positive parenting behavior. These findings suggest that the effectiveness of preventive interventions might be improved by targeting parent, school, and student outcomes, including outcome expectations, deviance acceptance, and social norms for both boys and girls, peer influences among boys, and self-control among girls.

Determinants of the fidelity of processing glucoamylase-lysozyme fusions by Aspergillus niger.

Fusion proteins are used to enhance the yields of heterologous proteins secreted from filamentous fungi. In Aspergillus niger, the target protein is normally fused downstream of the carrier protein glucoamylase with a Lys-Arg KEX2-like cleavage site at the junction. This is cleaved in vivo to release mature protein but the processing is not always accurate. We have used N-terminal mutant lysozymes to vary the sequence immediately downstream of the KEX site, and also varied the amino acid sequence upstream of the KEX processing site, to study the fidelity of processing. The sequences both upstream and downstream of the KEX2 site affected the fidelity of cleavage. With some constructs, a range of processing sites were apparent and the relative proportions were time dependent in batch cultures of A. niger. Aberrant processing was related to the secondary-structure preferences of the amino acids in and around the KEX site. Downstream of the processing site, the fidelity of processing decreased in proportion to the tendency for helix formation.

Considering a decision-making approach to youth violence prevention programs.

The unfortunate exception to a general downturn in violent crime involves an upsurge in violence among youth. Violence often results when minor confrontations escalate. As school violence increasingly has become widespread, schools have become the location of many violence prevention efforts, few of which have been evaluated adequately. This paper focuses on enhancing decision-making skills as one approach to increase adolescents' ability to manage interpersonal violence. Adolescents can be considered fairly skilled decision-makers and their unique perspective must be considered in development of effective intervention programs. Data from a pilot study were examined for insights about adolescents' ability to make decisions in situations of interpersonal conflict.

Structural characterisation and comparison of the native and A-states of equine lysozyme.

Native state 1H NMR resonance assignments for 125 of the 129 residues of equine lysozyme have enabled measurement of the hydrogen exchange kinetics for over 60 backbone amide and three tryptophan indole hydrogen atoms in the native state. Native holo equine lysozyme hydrogen exchange protection factors are as large as 10(6), the most protected residues being located in elements of secondary structure. High exchange protection in the domain interface correlates with the binding of Ca2+ in this region. Equine lysozyme differs from most non-Ca2+ binding lysozymes in forming a highly populated partially folded state at low pH. The protein in this A-state at pH 2.0 has been found to bind 1-anilino-naphthalene-8-sulphonate with the enhancement of fluorescent intensity and blue shift in the spectral maximum characteristic of molten globules. NMR spectra indicate that the A-state is globally much less ordered than native equine lysozyme but does not contain significant regions of random coil structure. The amides most protected against hydrogen exchange in the A-state (protection factors up to 10(2) at 5 degrees C) correspond to residues of three of the four alpha-helices of the native state; the side-chains of these residues form a hydrophobic cluster that includes five aromatic residues. Circular dichroism and tryptophan fluorescence indicate that these residues are substantially more constrained than similar residues in "classical" molten globules. Taken together, the data suggest a model for the A-state of equine lysozyme in which a more ordered core is surrounded by a less ordered but still compact polypeptide chain.

The N-terminal domains of tensin and auxilin are phosphatase homologues.

Tensin, an actin filament capping protein, and auxilin, a component of receptor-mediated endocytosis, are known to have 350 residue regions of significant sequence similarity near their N-termini (Schröder et al., 1995, Eur J Biochem 228:297-304). Here we demonstrate that these regions are homologous, not only to each other, but also to the catalytic domain of a putative protein tyrosine phosphatase (PTP) from Saccharomyces cerevisiae and to other PTPs. We propose that the PTP-like portion of the homology region of tensin and auxilin represents a distinct domain. A detailed sequence comparison indicates that the PTP-like domain in tensin is unlikely to exhibit phosphatase activity, whereas in auxilin it may possess a different phosphatase specificity from tyrosine phosphatases. It is probable that the PTP-like domains in tensin and auxilin mediate binding interactions with phosphorylated polypeptides; they may therefore represent members of a distinct class of phosphopeptide recognition domain.