Predicting enzyme class from protein structure using Bayesian classification

Predicting enzyme class from protein structure parameters is a challenging problem in protein analysis. We developed a method to predict enzyme class that combines the strengths of statistical and data-mining methods. This method has a strong mathematical foundation and is simple to implement, achieving an accuracy of 45%. A comparison with the methods found in the literature designed to predict enzyme class showed that our method outperforms the existing methods.

Building multiple sequence alignments with a flavor of HSSP alignments

Homology-derived secondary structure of proteins (HSSP) is a well-known database of multiple sequence alignments (MSAs) which merges information of protein sequences and their three-dimensional structures. It is available for all proteins whose structure is deposited in the PDB. It is also used by STING and (Java)Protein Dossier to calculate and present relative entropy as a measure of the degree of conservation for each residue of proteins whose structure has been solved and deposited in the PDB. However, if the STING and (Java)Protein Dossier are to provide support for analysis of protein structures modeled in computers or being experimentally solved but not yet deposited in the PDB, then we need a new method for building alignments having a flavor of HSSP alignments (myMSAr). The present study describes a new method and its corresponding databank (SH2QS--database of sequences homologue to the query [structure-having] sequence). Our main interest in making myMSAr was to measure the degree of residue conservation for a given query sequence, regardless of whether it has a corresponding structure deposited in the PDB. In this study, we compare the measurement of residue conservation provided by corresponding alignments produced by HSSP and SH2QS. As a case study, we also present two biologically relevant examples, the first one highlighting the equivalence of analysis of the degree of residue conservation by using HSSP or SH2QS alignments, and the second one presenting the degree of residue conservation for a structure modeled in a computer, which , as a consequence, does not have an alignment reported by HSSP.

The Star STING server: a multiplatform environment for protein structure analysis

Star STING is the latest version of the STING suite of programs and corresponding database. We report on five important aspects of this package that have acquired some new characteristics, designed to add key advantages to the whole suite: 1) availability for most popular platforms and browsers, 2) introduction of the STING_DB quality assessment, 3) improvement in algorithms for calculation of three STING parameters, 4) introduction of five new STING modules, and 5) expansion of the existing modules. Star STING is freely accessible at: http://sms.cbi.cnptia.embrapa.br/SMS/, http://trantor.bioc.columbia.edu/SMS, http://www.es.embnet.org/SMS/, http://gibk26.bse.kyutech.ac.jp/SMS/ and http://www.ar.embnet.org/SMS.

PDB-Metrics: a web tool for exploring the PDB contents

PDB-Metrics (http://sms.cbi.cnptia.embrapa.br/SMS/pdb_metrics/index.html) is a component of the Diamond STING suite of programs for the analysis of protein sequence, structure and function. It summarizes the characteristics of the collection of protein structure descriptions deposited in the Protein Data Bank (PDB) and provides a Web interface to search and browse the PDB, using a variety of alternative criteria. PDB-Metrics is a powerful tool for bioinformaticians to examine the data span in the PDB from several perspectives. Although other Web sites offer some similar resources to explore the PDB contents, PDB-Metrics is among those with the most complete set of such facilities, integrated into a single Web site. This program has been developed using SQLite, a C library that provides all the query facilities of a database management system

Prolactina: regulación y secreción en algunos estados fisiológicos / Prolactin: its regulation and secretion in some physiologic states

La prolactina es una hormona cuya acción fisiológica más importante es su participación en el desarrollo mamario y en la inducción de la lactancia. Es a partir de 1970 que se obtuvo una clara demostración de su existencia en el plasma humano como hormona diferente de la somatotrofina, es secretada por la glándula hipófisis y se halla bajo un control tónico predominantemente inhibidor del hipotálamo, a través de un péptido aún no caracterizado químicamente llamado Prolactin Inhibiting Factor (PIF), aunque se postula que la dopamina sería la mayor responsable de la inhibición de esta hormona. Los niveles de prolactina sérica varían con la edad hasta llegar a las concentraciones de 5-10 ng/ml en la mujer adulta normal, para disminuir a partir de la menopausia. Nuestro grupo investigó esta hormona en diversas condiciones fisiológicas y en diferentes etapas de la vida : en el nacimiento, pubertad; hombre y mujer adulta, durante el embarazo, en donde se observa un aumento progresivo a partir de la séptima semana hasta el término; y durante la lactancia. Estos estudios se realizaron en condiciones basales y mediante pruebas de estimulación de prolactina: sulpirida y TRH (hormona liberada de tirotrofina), y de inhibición con la administración de bromocriptina, L-dopa. Nuestros mayores esfuerzos fueron efectuados en el estudio de las condiciones patológicas de hiperprolactinemia. Pudimos comprobar que esta podía ser la causa farmacológica, por la administración de drogas tales como sulpirida, metoclopramida, alfa metil dopa, antidepresivos tricíclicos, cimetidina; hiperprolactinemia funcional cuando no pudimos demostrar la presencia de un adenoma hipofisiario; y orgánica cuando el adenoma era radiológicamente y quirúrgicamente demostrable. El control de la hiperprolactinemia mediante la estirpación selectiva del adenoma por la vía transeptoesfenoidal o por medio de la bromocriptina nos permitió además grandes avances en el terreno de la fertilidad tanto en el hombre como en la mujer.