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1.
J Biomech ; 159: 111774, 2023 10.
Article in English | MEDLINE | ID: mdl-37690367

ABSTRACT

There is a lack of knowledge about the accuracy of the Conventional Gait Model (CGM), compared to the true bone motion. Accuracy is hindered by both marker misplacement and soft-tissue artefact (STA). The effect of the lateral knee marker (KNE) misplacement and STA was determined from a secondary analysis of 13 subjects equipped with a total knee prothesis for which simultaneous dual-plane fluoroscopy and marker-based motion capture was available. In average, STA alone led to 3.3°, 2.9° and 6.7° errors for knee flexion, knee abduction, and the absolute hip rotation respectively. In comparison, marker misplacement led to 0.9°, 4.0° and 12.3° errors for the same kinematics. We showed that STA alone may lead to knee flexion-adduction cross-talk. This finding has clinical repercussions for the use of knee cross talk as a qualitative indicator of knee axis alignment. Our study showed that cumulative effects of marker misplacement and STA affect the transverse plane angles, making challenging to track internal/external rotation with less than 5° of errors.


Subject(s)
Artifacts , Gait , Humans , Knee Joint , Knee , Lower Extremity , Biomechanical Phenomena
2.
J Crohns Colitis ; 17(11): 1723-1732, 2023 Nov 24.
Article in English | MEDLINE | ID: mdl-37279927

ABSTRACT

BACKGROUND AND AIMS: Herein we analysed the influence of early life factors, including breast milk composition, on the development of the intestinal microbiota of infants born to mothers with and without IBD. METHODS: The MECONIUM [Exploring MEChanisms Of disease traNsmission In Utero through the Microbiome] study is a prospective cohort study consisting of pregnant women with or without IBD and their infants. Longitudinal stool samples were collected from babies and analysed using 16s rRNA sequencing and faecal calprotectin. Breast milk proteomics was profiled using Olink inflammation panel. RESULTS: We analysed gut microbiota of 1034 faecal samples from 294 infants [80 born to mothers with and 214 to mothers without IBD]. Alpha diversity was driven by maternal IBD status and time point. The major influencers of the overall composition of the microbiota were mode of delivery, feeding, and maternal IBD status. Specific taxa were associated with these exposures, and maternal IBD was associated with a reduction in Bifidobacterium. In 312 breast milk samples [91 from mothers with IBD], mothers with IBD displayed lower abundance of proteins involved in immune regulation, such as thymic stromal lymphopoietin, interleukin-12 subunit beta, tumour necrosis factor-beta, and C-C motif chemokine 20, as compared with control mothers [adjusted p = 0.0016, 0.049, 0.049, and 0.049, respectively], with negative correlations with baby´s calprotectin, and microbiome at different time points. CONCLUSION: Maternal IBD diagnosis influences microbiota in their offspring during early life. The proteomic profile of breast milk of women with IBD differs from that of women without IBD, with distinct time-dependent associations with baby's gut microbiome and feacal calprotectin.


Subject(s)
Inflammatory Bowel Diseases , Microbiota , Infant , Female , Humans , Pregnancy , Milk, Human/chemistry , Prospective Studies , RNA, Ribosomal, 16S/genetics , Proteomics , Inflammatory Bowel Diseases/metabolism , Feces/chemistry , Leukocyte L1 Antigen Complex/analysis , Mothers
3.
Tech Coloproctol ; 27(12): 1201-1210, 2023 12.
Article in English | MEDLINE | ID: mdl-36811811

ABSTRACT

BACKGROUND: The injection of allogeneic adipose tissue-derived mesenchymal stem cells (MSC) into anal fistulas in patients with Crohn's disease has never been evaluated in "real-life" conditions in France. METHODS: We prospectively studied the first patients receiving MSC injections at our center and undergoing 12 months of follow-up. The primary endpoint was the clinical and radiological response rate. The secondary endpoints were symptomatic efficacy, safety, anal continence, quality of life (Crohn's anal fistula-quality of life scale, CAF-QoL), and predictive factors of success. RESULTS: We included 27 consecutive patients. The complete clinical and radiological response rates at M12 were 51.9% and 50%, respectively. The combined complete clinical-radiological response (deep remission) rate was 34.6%. No major adverse effects or changes in anal continence were reported. The perianal disease activity index decreased from 6.4 to 1.6 (p < 0.001) for all patients. The CAF-QoL score also decreased from 54.0 to 25.5 (p < 0.001). At the end of the study, M12, the CAF-QoL score was significantly lower only in patients with a complete combined clinical-radiological response relative to those without a complete clinical-radiological response (15.0 versus 32.8, p = 0.01). Having a multibranching fistula and infliximab treatment were associated with a combined complete clinical-radiological response. CONCLUSIONS: This study confirms reported efficacy data for the injection of MSC for complex anal fistulas in Crohn's disease. It also shows a positive impact on the quality of life of patients, particularly those for whom a combined clinical-radiological response was achieved.


Subject(s)
Crohn Disease , Rectal Fistula , Humans , Crohn Disease/complications , Crohn Disease/therapy , Quality of Life , Pilot Projects , Treatment Outcome , Rectal Fistula/therapy , Rectal Fistula/complications
4.
Tech Coloproctol ; 27(2): 165-166, 2023 02.
Article in English | MEDLINE | ID: mdl-35996043
5.
Front Allergy ; 3: 877553, 2022.
Article in English | MEDLINE | ID: mdl-36157274

ABSTRACT

About 10 years ago, a protein family was shown for the first time to contain allergenic members, gibberellin-regulated protein (GRP). The first reported member was from peach, Pru p 7. One can hypothesize that it was not detected before because its physicochemical characteristics overlap with those of lipid transfer protein (LTP), a well-known allergen, or because the exposure to GRP increased due to an increase in the gibberellin phythormone level in plant food, either exogenous or endogenous. Like LTPs, GRPs are small cationic proteins with disulfide bridges, are resistant to heat and proteolytic cleavage, and are involved in the defense of the plant. Besides peach, GRP allergens have been described in Japanese apricot (Pru m 7), sweet cherry (Pru av 7), orange (Cit s 7), pomegranate (Pun g 7), bell pepper (Cap a 7), strawberry (Fra a GRP), and also in pollen with a restriction to Cupressaceae tree family (Cup s 7, Cry j 7, and Jun a 7). IgE cross-reactivities were described between GRPs, and the reported peach/cypress and citrus/cypress syndromes may therefore be explained because of these GRP cross-reactivities. GRPs are clinically relevant, and severe adverse reactions may sometimes occur in association with cofactors. More than 60% and up to 95% sequence identities are calculated between various allergenic GRPs, and three-dimensional models show a cleft in the molecule and predict at least three epitopic regions. The structure of the protein and its properties and the matrix effect in the original allergenic source should be unraveled to understand why, despite the ubiquity of the protein family in plants, only a few members are able to sensitize patients.

6.
Pharmacol Ther ; 210: 107517, 2020 06.
Article in English | MEDLINE | ID: mdl-32109491

ABSTRACT

Biliary tract cancers (BTCs) represent a heterogeneous group that includes intrahepatic cholangiocarcinomas (CCAs), perihilar-CCAs or Klatskin tumors, extrahepatic-CCAs, and gallbladder adenocarcinoma. These entities have distinct demographics, risk factors, clinical presentation, and molecular characteristics. In advanced BTCs, the recommendations are mainly supporting a doublet chemotherapy regimen using cisplatin/gemcitabine (CisGem) with a 5-year overall survival rate close to 5% and median overall survival (mOS) of less than a year. The lack of overall efficacy stresses the need for personalized therapies. Recently, whole-genome and transcriptome sequencing highlighted the diversity of BTCs' subtypes. Distinct genetic alterations were retrieved according to the localization, with a high rate of potentially actionable alterations. Targeted therapies and immunotherapy have since then been tested for BTCs, trying to propose a more personalized treatment. This review describes the different therapeutic options, validated and in development, for patients with advanced BTCs.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Biliary Tract Neoplasms/therapy , Immunotherapy , Molecular Targeted Therapy , Antineoplastic Combined Chemotherapy Protocols/adverse effects , Biliary Tract Neoplasms/genetics , Biliary Tract Neoplasms/immunology , Biliary Tract Neoplasms/mortality , Biomarkers, Tumor/genetics , Clinical Decision-Making , Humans , Immunotherapy/adverse effects , Immunotherapy/mortality , Molecular Targeted Therapy/adverse effects , Molecular Targeted Therapy/mortality , Precision Medicine , Treatment Outcome , Tumor Microenvironment
7.
Gait Posture ; 69: 235-241, 2019 03.
Article in English | MEDLINE | ID: mdl-31027876

ABSTRACT

BACKGROUND: The Conventional Gait Model (CGM), known by a variety of different names, is widely used in clinical gait analysis. We present pyCGM2, an open-source implementation of the CGM with two versions. The first, CGM1.0, is a clone of Vicon Plug In Gait (PiG) with all its variants. CGM1.0 provides a platform to test the effect of modifications to the CGM on data collected and processed retrospectively or to provide backward compatibility. The second version, CGM1.1, offers some practical modifications and includes three well documented improvements. RESEARCH QUESTION: How do improvements of the conventional gait model affect joint kinematics and kinetics? METHOD: The practical modifications include the possibility to use a medial knee epicondyle marker, during static calibration only, to define the medio-lateral axis of the femur in place of the knee alignment device. The three improvements correspond to the change of pelvis angle decomposition sequence, the adoption of a single tibia coordinate system, and the default decomposition of the joint moments in the joint coordinate system. We validated the outputs of version CGM1.0 against Vicon-PiG, and estimated the effect of the modifications included in version CGM1.1 using gait data collected in 16 healthy participants. RESULTS: Kinematics and kinetics of CGM1.0 were superimposed with that of Vicon-PiG, with root mean square differences less than 0.04° for kinematics and less than 0.05 N.m.kg-1 for kinetics. SIGNIFICANCE: The differences between the CGM1.1 and CGM1.0 were minimal in the healthy participant cohort but we discussed the expected difference in participants with different gait pathologies. We hope that the pyCGM2 will facilitate the systematic testing and the use of improved processing methods for the conventional gait model.


Subject(s)
Gait Analysis/methods , Knee Joint/physiology , Models, Biological , Software , Adult , Biomechanical Phenomena , Calibration , Female , Healthy Volunteers , Humans , Kinetics , Male , Middle Aged , Retrospective Studies
8.
Gait Posture ; 69: 126-129, 2019 Jan 23.
Article in English | MEDLINE | ID: mdl-30708095

ABSTRACT

BACKGROUND: The Conventional Gait Model (CGM), known by a variety of different names, is widely used in clinical gait analysis. We present pyCGM2, an open-source implementation of the CGM with two versions. The first, CGM1.0, is a clone of Vicon Plug In Gait (PiG) with all its variants. CGM1.0 provides a platform to test the effect of modifications to the CGM on data collected and processed retrospectively or to provide backward compatibility. The second version, CGM1.1, offers some practical modifications and includes three well documented improvements. RESEARCH QUESTION: How do improvements of the conventional gait model affect joint kinematics and kinetics? METHOD: The practical modifications include the possibility to use a medial knee epicondyle marker, during static calibration only, to define the medio-lateral axis of the femur in place of the knee alignment device. The three improvements correspond to the change of pelvis angle decomposition sequence, the adoption of a single tibia coordinate system, and the default decomposition of the joint moments in the joint coordinate system. We validated the outputs of version CGM1.0 against Vicon-PiG, and estimated the effect of the modifications included in version CGM1.1 using gait data collected in 16 healthy participants. RESULTS: Kinematics and kinetics of CGM1.0 were superimposed with that of Vicon-PiG, with root mean square differences less than 0.04° for kinematics and less than 0.05 N.m.kg-1 for kinetics. SIGNIFICANCE: The differences between the CGM1.1 and CGM1.0 were minimal in the healthy participant cohort but we discussed the expected difference in participants with different gait pathologies. We hope that the pyCGM2 will facilitate the systematic testing and the use of improved processing methods for the conventional gait model.

9.
Aliment Pharmacol Ther ; 47(7): 896-905, 2018 Apr.
Article in English | MEDLINE | ID: mdl-29430672

ABSTRACT

BACKGROUND: Increased knowledge of pathways involved in the pathogenesis of IBD has led to the development of new treatment options for Crohn's disease (CD) and ulcerative colitis (UC). Two new biological agents have been recently approved for IBD: vedolizumab and ustekinumab. They have different therapeutic targets (α4 ß7 integrin for vedolizumab and interleukin-12/23 pathways for ustekinumab) than the primary biological class, anti-tumour necrosis factor alpha (anti-TNF) agents. As the armamentarium for IBD increases in coming years, it will become important to understand factors associated with response in order to best position and personalise therapy. AIM: To summarise the current data on predictors of response to vedolizumab and ustekinumab in IBD patients. METHODS: We conducted a comprehensive literature review. A PubMed search was performed using pre-defined key words and terms to identify relevant studies on predictors of response. RESULTS: Patients with severe disease (by clinical activity and inflammatory biomarkers), or prior anti-TNF exposure are less likely to respond to vedolizumab. Ileocolonic disease, no prior surgery and uncomplicated phenotype were associated with better responses to ustekinumab in CD. Initial response seems to predict a better long-term maintenance in both therapies (P < 0.001). Contrary to anti-TNF therapies, immunogenicity appears to play less of a role in response. CONCLUSION: As the number of new biological therapies increase in IBD, identifying patients who are most likely to benefit from specific agents is of paramount importance to help best position IBD therapies.


Subject(s)
Antibodies, Monoclonal, Humanized/therapeutic use , Inflammatory Bowel Diseases/diagnosis , Inflammatory Bowel Diseases/drug therapy , Ustekinumab/therapeutic use , Biomarkers, Pharmacological/analysis , Colitis, Ulcerative/diagnosis , Colitis, Ulcerative/drug therapy , Crohn Disease/diagnosis , Crohn Disease/drug therapy , Gastrointestinal Agents/therapeutic use , Humans , Prognosis , Treatment Outcome
11.
Clin Exp Immunol ; 176(2): 266-74, 2014 May.
Article in English | MEDLINE | ID: mdl-24450998

ABSTRACT

Inflammatory bowel diseases are characterized by a deregulated immune response targeting the gut bacterial flora. Mucosal-associated invariant T (MAIT) cells are major histocompatibility complex (MHC) class Ib-restricted innate-like lymphocytes with anti-bacterial functions. They display an effector/memory phenotype and are found in large numbers in the blood, mucosae and liver. They have also been implicated in inflammatory diseases such as multiple sclerosis. Therefore, we aimed to analyse the possible involvement of MAIT cells in Crohn's disease (CD) and ulcerative colitis (UC). To this end, a phenotypical and functional analysis of MAIT cells isolated from the blood of healthy subjects, CD and UC patients was undertaken. MAIT cells were also quantified in ileal biopsies of CD patients. The frequency of blood MAIT cells was specifically reduced in IBD patients compared with healthy donors, whereas it was dramatically greater in the inflamed versus healthy tissue. MAIT cells were activated as they expressed significantly more the Ki67 antigen, and this was accompanied by phenotypical changes such as increased expression of natural killer (NK)G2D and B and T lymphocyte attenuator (BTLA). Finally, in-vitro-activated MAIT cells from CD and UC patients secreted significantly more interleukin (IL)-17, together with a decreased interferon (IFN)-γ in CD but an increased IL-22 in UC. These data show that MAIT cells are activated in IBD, which results in an increased recruitment towards the inflamed tissues, an altered phenotype and a switch in the pattern of cytokine secretion. This is the first demonstration that MAIT cells are immune players in IBD, whose precise functions in this context need to be addressed.


Subject(s)
Inflammatory Bowel Diseases/immunology , Intestinal Mucosa/immunology , Natural Killer T-Cells/immunology , T-Lymphocyte Subsets/immunology , Adult , Colitis, Ulcerative/blood , Colitis, Ulcerative/immunology , Colitis, Ulcerative/pathology , Crohn Disease/blood , Crohn Disease/immunology , Crohn Disease/pathology , Female , Flow Cytometry , Humans , Immunity, Innate/immunology , Inflammatory Bowel Diseases/blood , Inflammatory Bowel Diseases/pathology , Interferon-gamma/blood , Interferon-gamma/immunology , Interleukin-17/blood , Interleukin-17/immunology , Interleukins/blood , Interleukins/immunology , Intestinal Mucosa/pathology , Ki-67 Antigen/immunology , Ki-67 Antigen/metabolism , Lymphocyte Activation/immunology , Male , Microscopy, Confocal , NK Cell Lectin-Like Receptor Subfamily K/immunology , NK Cell Lectin-Like Receptor Subfamily K/metabolism , Natural Killer T-Cells/metabolism , Natural Killer T-Cells/pathology , Receptors, Immunologic/immunology , Receptors, Immunologic/metabolism , T-Lymphocyte Subsets/metabolism , T-Lymphocyte Subsets/pathology , Interleukin-22
14.
Plant Physiol Biochem ; 44(10): 535-42, 2006 Oct.
Article in English | MEDLINE | ID: mdl-17064926

ABSTRACT

The localization and distribution of non-specific lipid transfer proteins (nsLTP) allergens in the skin and pulp of Rosaceae fruits (apple, peach, apricot, plum) has been investigated. nsLTP essentially concentrate in the pericarp of the fruits whereas the pulp contains lower amounts of allergens. Immunolocalization showed they are primarily located in the cytosol but are subsequently excreted and finally accumulate at the plasmalemma-cell wall interface and in the cell wall. However, high discrepancies were observed in the content of allergens among, e.g. different cultivars of apple. As a consequence, the consumption of peeled-off fruits is recommended to reduce the risk of severe allergic reactions (anaphylactic shock) in individuals sensitized to Rosaceae fruits.


Subject(s)
Allergens/immunology , Antigens, Plant/metabolism , Carrier Proteins/metabolism , Fruit/cytology , Fruit/metabolism , Membrane Proteins/metabolism , Plant Proteins/metabolism , Rosaceae/cytology , Rosaceae/metabolism , Antigens, Plant/chemistry , Antigens, Plant/immunology , Carrier Proteins/chemistry , Carrier Proteins/immunology , Fruit/immunology , Membrane Proteins/chemistry , Membrane Proteins/immunology , Models, Molecular , Plant Proteins/chemistry , Plant Proteins/immunology , Protein Conformation , Protein Transport , Rosaceae/immunology
15.
Acta Crystallogr D Biol Crystallogr ; 58(Pt 4): 627-33, 2002 Apr.
Article in English | MEDLINE | ID: mdl-11914487

ABSTRACT

The structure of a catalytically inactive RNase-related protein from Calystegia sepium (CalsepRRP) has been resolved by protein crystallography at a resolution of 2.05 A and an R factor of 20.74%. Although the protein is completely devoid of ribonuclease activity, it adopts the typical alpha + beta structure of non-base-specific RNases. Analysis of the structure revealed that two amino-acid substitutions in the 'active' P1 site, in combination with the less hydrophobic/aromatic character of the B1 base-recognition site and a completely disrupted B2 base-recognition site, might account for this complete lack of activity.


Subject(s)
Plant Proteins/chemistry , Amino Acid Sequence , Binding Sites , Crystallography, X-Ray , Models, Molecular , Molecular Sequence Data , Protein Structure, Secondary , Sequence Alignment
16.
Eur J Biochem ; 268(23): 6263-73, 2001 Dec.
Article in English | MEDLINE | ID: mdl-11733023

ABSTRACT

An abundant catalytically active beta-amylase (EC 3.2.1.2) was isolated from resting rhizomes of hedge bindweed (Calystegia sepium). Biochemical analysis of the purified protein, molecular modeling, and cloning of the corresponding gene indicated that this enzyme resembles previously characterized plant beta-amylases with regard to its amino-acid sequence, molecular structure and catalytic activities. Immunolocalization demonstrated that the beta-amylase is exclusively located in the cytoplasm. It is suggested that the hedge bindweed rhizome beta-amylase is a cytoplasmic vegetative storage protein.


Subject(s)
Magnoliopsida/enzymology , beta-Amylase/isolation & purification , beta-Amylase/metabolism , Amino Acid Sequence , Cloning, Molecular , Cytoplasm/enzymology , Immunohistochemistry , Kinetics , Magnoliopsida/genetics , Models, Molecular , Molecular Sequence Data , Plant Proteins/chemistry , Plant Proteins/genetics , Plant Proteins/isolation & purification , Plant Proteins/metabolism , Protein Conformation , Rhizome/enzymology , Sequence Homology, Amino Acid , beta-Amylase/chemistry , beta-Amylase/genetics
17.
EMBO J ; 20(22): 6383-93, 2001 Nov 15.
Article in English | MEDLINE | ID: mdl-11707409

ABSTRACT

We have studied the role of individual histone N-termini and the phosphorylation of histone H3 in chromosome condensation. Nucleosomes, reconstituted with histone octamers containing different combinations of recombinant full-length and tailless histones, were used as competitors for chromosome assembly in Xenopus egg extracts. Nucleosomes reconstituted with intact octamers inhibited chromosome condensation as efficiently as the native ones, while tailless nucleosomes were unable to affect this process. Importantly, the addition to the extract of particles containing only intact histone H2B strongly interfered with chromosome formation while such an effect was not observed with particles lacking the N-terminal tail of H2B. This demonstrates that the inhibition effect observed in the presence of competitor nucleosomes is mainly due to the N-terminus of this histone, which, therefore, is essential for chromosome condensation. Nucleosomes in which all histones but H3 were tailless did not impede chromosome formation. In addition, when competitor nucleosome particles were reconstituted with full-length H2A, H2B and H4 and histone H3 mutated at the phosphorylable serine 10 or serine 28, their inhibiting efficiency was identical to that of the native particles. Hence, the tail of H3, whether intact or phosphorylated, is not important for chromosome condensation. A novel hypothesis, termed 'the ready production label' was suggested to explain the role of histone H3 phosphorylation during cell division.


Subject(s)
Chromosomes/metabolism , Histones/chemistry , Animals , Binding, Competitive , Cell Nucleus/metabolism , Cysteine Endopeptidases/pharmacology , Deoxyribonuclease I/metabolism , Fluorescent Antibody Technique, Indirect , Immunoblotting , Kinetics , Male , Microscopy, Fluorescence , Mitosis , Models, Biological , Mutation , Nucleosomes/metabolism , Ovum , Phosphorylation , Protein Structure, Tertiary , Recombinant Proteins/metabolism , Serine/chemistry , Serine/metabolism , Spermatozoa/metabolism , Time Factors , Trypsin/pharmacology , Xenopus
18.
Neuropsychologia ; 39(13): 1444-50, 2001.
Article in English | MEDLINE | ID: mdl-11585612

ABSTRACT

Responding correctly to a mirror image requires the creation of a rather peculiar form of dual representation. Mirror agnosia and mirror ataxia, i.e. a deficit in reaching an object reflected in a mirror, have been reported to be associated with parietal lobe lesions. This prospective study was conducted to investigate the capacity of subjects with neglect to identify the mirror image nature of visual information. Four consecutive brain-damaged patients with neglect, selected on the basis of specific criteria, and four control subjects performed grasping and object displacement tests under two response conditions (normal mirror and inverted mirror). Video recordings of the tests were analyzed to assess performance using the following criteria: (i) direction of the arm movement during the initial phase of movement, (ii) number of corrections of the hand position before grasping. The control subjects successfully grasped the objects in both experimental conditions. The patients (1) neglected the contralesional space, grasping objects correctly in the ipsilesional space (normal mirror condition) and (2) neglected the ipsilesional space, grasping correctly objects in the contralesional space (inverted mirror). Controls used real object-centered correction clues to modify the position and direction of their hand movement. The patients only produced horizontal displacements of the upper limb in the "healthy" and neglected space. These results suggest that patients with neglect do not use the same clues and do not modify their procedures as they cannot recalibrate their spatial representations. These differences concerned non-mirror-image clues and directional and positional as well as attentional vectors. Theoretical and rehabilitative implications are discussed.


Subject(s)
Dominance, Cerebral , Perceptual Disorders/etiology , Psychomotor Performance , Stroke/physiopathology , Visual Perception , Adult , Case-Control Studies , Cues , Female , Hemiplegia/etiology , Humans , Male , Middle Aged , Stroke/psychology
19.
Biochimie ; 83(7): 645-51, 2001 Jul.
Article in English | MEDLINE | ID: mdl-11522393

ABSTRACT

Mannose-specific lectins are widely distributed in higher plants and are believed to play a role in recognition of high-mannose type glycans of foreign micro-organisms or plant predators. Structural studies have demonstrated that the mannose-binding specificity of lectins is mediated by distinct structural scaffolds. The mannose/glucose-specific legume (e.g., Con A, pea lectin) exhibit the canonical twelve-stranded beta-sandwich structure. In contrast to legume lectins that interact with both mannose and glucose, the monocot mannose-binding lectins (e.g., the Galanthus nivalis agglutinin or GNA from bulbs) react exclusively with mannose and mannose-containing N-glycans. These lectins possess a beta-prism structure. More recently, an increasing number of mannose-specific lectins structurally related to jacalin (e.g., the lectins from the Jerusalem artichoke, banana or rice), which also exhibit a beta-prism organization, were characterized. Jacalin itself was re-defined as a polyspecific lectin which, in addition to galactose, also interacts with mannose and mannose-containing glycans. Finally the B-chain of the type II RIP of iris, which has the same beta-prism structure as all other members of the ricin-B family, interacts specifically with mannose and galactose. This structural diversity associated with the specific recognition of high-mannose type glycans highlights the importance of mannose-specific lectins as recognition molecules in higher plants.


Subject(s)
Lectins/metabolism , Mannose/metabolism , N-Glycosyl Hydrolases/metabolism , Plant Proteins/metabolism , Binding Sites , Carrier Proteins/chemistry , Collectins , Galactose/metabolism , Glucose/metabolism , Lectins/chemistry , Models, Molecular , Plant Lectins , Plants , Protein Binding , Protein Structure, Quaternary , Protein Structure, Secondary , Protein Structure, Tertiary , Ribosome Inactivating Proteins, Type 2
20.
Proteins ; 44(4): 470-8, 2001 Sep 01.
Article in English | MEDLINE | ID: mdl-11484224

ABSTRACT

The structure of the bark lectin RPbAI (isoform A4) from Robinia pseudoacacia has been determined by protein crystallography both in the free form and complexed with N-acetylgalactosamine. The free form is refined at 1.80 A resolution to an R-factor of 18.9% whereas the complexed structure has an R-factor of 19.7% at 2.05 A resolution. Both structures are compared to each other and to other available legume lectin structures. The polypeptide chains of the two structures exhibit the characteristic legume lectin tertiary fold. The quaternary structure resembles that of the Phaseolus vulgaris lectin, the soybean agglutinin, and the Dolichos biflorus lectin, but displays some unique features leading to the extreme stability of this lectin.


Subject(s)
Acacia/chemistry , Acetylglucosamine/metabolism , Lectins/chemistry , Lectins/metabolism , Acetylglucosamine/chemistry , Binding Sites , Crystallography, X-Ray , Hydrogen Bonding , Models, Molecular , Plant Lectins , Protein Binding , Protein Conformation , Static Electricity , Water/chemistry , Water/metabolism
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