Cupricyclins, novel redox-active metallopeptides based on conotoxins scaffold.

Highly stable natural scaffolds which tolerate multiple amino acid substitutions represent the ideal starting point for the application of rational redesign strategies to develop new catalysts of potential biomedical and biotechnological interest. The knottins family of disulphide-constrained peptides display the desired characteristics, being highly stable and characterized by hypervariability of the inter-cysteine loops. The potential of knottins as scaffolds for the design of novel copper-based biocatalysts has been tested by engineering a metal binding site on two different variants of an ω-conotoxin, a neurotoxic peptide belonging to the knottins family. The binding site has been designed by computational modelling and the redesigned peptides have been synthesized and characterized by optical, fluorescence, electron spin resonance and nuclear magnetic resonance spectroscopy. The novel peptides, named Cupricyclin-1 and -2, bind one Cu(2+) ion per molecule with nanomolar affinity. Cupricyclins display redox activity and catalyze the dismutation of superoxide anions with an activity comparable to that of non-peptidic superoxide dismutase mimics. We thus propose knottins as a novel scaffold for the design of catalytically-active mini metalloproteins.

Antioxidant properties of aminoethylcysteine ketimine decarboxylated dimer: a review.

Aminoethylcysteine ketimine decarboxylated dimer is a natural sulfur-containing compound detected in human plasma and urine, in mammalian brain and in many common edible vegetables. Over the past decade many studies have been undertaken to identify its metabolic role. Attention has been focused on its antioxidant properties and on its reactivity against oxygen and nitrogen reactive species. These properties have been studied in different model systems starting from plasma lipoproteins to specific cellular lines. All these studies report that aminoethylcysteine ketimine decarboxylated dimer is able to interact both with reactive oxygen and nitrogen species (hydrogen peroxide, superoxide anion, hydroxyl radical, peroxynitrite and its derivatives). Its antioxidant activity is similar to that of Vitamin E while higher than other hydrophilic antioxidants, such as trolox and N-acetylcysteine.

Spermine oxidase (SMO) activity in breast tumor tissues and biochemical analysis of the anticancer spermine analogues BENSpm and CPENSpm.

BACKGROUND: Polyamine metabolism has a critical role in cell death and proliferation representing a potential target for intervention in breast cancer (BC). This study investigates the expression of spermine oxidase (SMO) and its prognostic significance in BC. Biochemical analysis of Spm analogues BENSpm and CPENSpm, utilized in anticancer therapy, was also carried out to test their property in silico and in vitro on the recombinant SMO enzyme. METHODS: BC tissue samples were analyzed for SMO transcript level and SMO activity. Student's t test was applied to evaluate the significance of the differences in value observed in T and NT samples. The structure modeling analysis of BENSpm and CPENSpm complexes formed with the SMO enzyme and their inhibitory activity, assayed by in vitro experiments, were examined. RESULTS: Both the expression level of SMO mRNA and SMO enzyme activity were significantly lower in BC samples compared to NT samples. The modeling of BENSpm and CPENSpm complexes formed with SMO and their inhibition properties showed that both were good inhibitors. CONCLUSIONS: This study shows that underexpression of SMO is a negative marker in BC. The SMO induction is a remarkable chemotherapeutical target. The BENSpm and CPENSpm are efficient SMO inhibitors. The inhibition properties shown by these analogues could explain their poor positive outcomes in Phases I and II of clinical trials.

Norcoclaurine synthase: mechanism of an enantioselective pictet-spengler catalyzing enzyme.

The use of bifunctional catalysts in organic synthesis finds inspiration in the selectivity of enzymatic catalysis which arises from the specific interactions between basic and acidic amino acid residues and the substrate itself in order to stabilize developing charges in the transition state. Many enzymes act as bifunctional catalysts using amino acid residues at the active site as Lewis acids and Lewis bases to modify the substrate as required for the given transformation. They bear a clear advantage over non-biological methods for their ability to tackle problems related to the synthesis of enantiopure compounds as chiral building blocks for drugs and agrochemicals. Moreover, enzymatic synthesis may offer the advantage of a clean and green synthetic process in the absence of organic solvents and metal catalysts. In this work the reaction mechanism of norcoclaurine synthase is described. This enzyme catalyzes the Pictet-Spengler condensation of dopamine with 4-hydroxyphenylacetaldehyde (4-HPAA) to yield the benzylisoquinoline alkaloids central precursor, (S)-norcoclaurine. Kinetic and crystallographic data suggest that the reaction mechanism occurs according to a typical bifunctional catalytic process.

Características epidemiológicas de las defunciones por influenza A(H1N1) en la población asegurada de EsSalud-2009 / Epidemiologic features of deaths from influenza A (H1N1) 2009 in EsSalud insured population-2009

Objetivos: Determinar las características epidemiológicas de las defunciones por influenza A(H1N1) en la población asegurada de EsSalud-2009. Diseño: Estudio observacional, descriptivo de corte transversal. Lugar: Seguro Social del Perú - EsSalud. Participantes: Personas muertas por influenza A(H1N1). Intervenciones: La información se recolectó del sistema de vigilancia para Infección Respiratoria Aguda Grave y muertes asociadas de Influenza A(H1N1) de la población asegurada a nivel nacional. Se elaboró una base de datos y se procesó según características epidemiológicas de persona, tiempo y espacio, considerando las características clínicas y comorbilidad asociada. Principales medidas de resultados: Muertes por influenza A(H1N1). Resultados: Se registró un total de 74 muertes por influenza A(H1N1) durante el año 2009, 54 por ciento (40) hombres y 46 por ciento (34) mujeres. El grupo de edad que presentó mayor afectación fue el de 60 a más años, con 26 por ciento (19). La edad promedio de fallecimiento fue 41 años. Todos los pacientes fallecidos fueron hospitalizados y presentaron como síntomas principales fiebre y dificultad respiratoria. El 54 por ciento (40) presentó comorbilidad, principalmente enfermedades cardiovasculares, insuficiencia renal y obesidad. Según zona de procedencia, la mayoría de fallecimientos fue de Lima, seguido por Arequipa y el Cusco. Conclusiones: Las muertes presentadas por influenza A(H1N1) 2009 en los pacientes asegurados en EsSalud son similares a la tendencia nacional, en cuanto a su distribución por sexo. Donde se muestra una diferencia es en el grupo de edad que más fallecidos presentó: para el nivel nacional fue 50 a 59 años (18,2 por ciento), mientras que para EsSalud fue 60 a más años (26 por ciento). Asimismo, puede verse que la comorbilidad en los fallecidos en EsSalud (54 por ciento) fue menor a lo reportado por el Minsa para el nivel nacional (77,6 por ciento).

Objectives: To determine deaths from influenza A(H1N1) 2009 epidemiological characteristics in EsSalud insured population-2009. Design: Observational, descriptive, transversal study. Setting: Peruvian Social Security - EsSalud. Participants: Persons dead due to influenza A(H1N1). Interventions: The information was collected from the Surveillance for severe acute respiratory infections and Influenza A (H1N1) associated deaths of the insured population nationwide. A database was developed and processed according to time and space personsÆ epidemiological characteristics and considering clinical features like risk factors and associated comorbidities. Main outcome measures: Deaths due to influenza A(H1N1). Results: A total of 74 deaths from influenza AH1N1 were notified, 54 per cent (40) were men and 46 per cent (34) women; age group most involved was 60 and more years with 26 per cent of all deaths (19). Average age of death was 41 years. All dead patients were hospitalized and presented as main symptoms fever and respiratory distress; 54 per cent (40) had comorbidity mainly cardiovascular disease, renal failure and obesity. As for provenance, most deaths were from Lima, followed by Arequipa and Cusco. Conclusions: Deaths by influenza A (H1N1) 2009 features in EsSalud insured patients were similar to the national trend in terms of sex distribution. There was difference in the age group with most deaths; the national age group was 50 to 59 years (18,2 per cent) and for EsSalud 60 to more years (26 per cent). Comorbidity in those who died in EsSalud (54 per cent) was lower than that reported by Minsa at the national level (77,6 per cent).

Cupryphans, metal-binding, redox-active, redesigned conopeptides.

Contryphans are bioactive peptides, isolated from the venom of marine snails of the genus Conus, which are characterized by the short length of the polypeptide chain and the high degree of unusual post-translational modifications. The cyclization of the polypeptide chain through a single disulphide bond, the presence of two conserved Pro residues, and the epimerization of a Trp/Leu residue confer to Contryphans a stable and well-defined structure in solution, conserved in all members of the family, and tolerant to multiple substitutions. The potential of Contryphans as scaffolds for the design of redox-active (macro)molecules was tested by engineering a copper-binding site on two different variants of the natural peptide Contryphan-Vn. The binding site was designed by computational modeling, and the redesigned peptides were synthesized and characterized by optical, fluorescence, electron spin resonance, and nuclear magnetic resonance spectroscopy. The novel peptides, named Cupryphan and Arg-Cupryphan, bind Cu(2+) ions with a 1:1 stoichiometry and a K(d) in the 100 nM range. Other divalent metals (e.g., Zn(2+) and Mg(2+)) are bound with much lower affinity. In addition, Cupryphans catalyze the dismutation of superoxide anions with an activity comparable to other nonpeptidic superoxide dismutase mimics. We conclude that the Contryphan motif represents a natural robust scaffold which can be engineered to perform different functions, providing additional means for the design of catalytically active mini metalloproteins.