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Effects of phosphorylation on 3D conformation of proteins
Tomčalová, Brenda ; Novotný, Marian (advisor) ; Vymětal, Jiří (referee)
Phosphorylation is one of the most ubiquitous posttranslational modification types. Understanding of itsfunction and regulation has significant impact on diagnosis and treatment of many diseases. This thesis presents and summarizes the results of several publications that analyze phosphorylation on large datasets using bioinformatics tools. In this thesis the general principles how the phosphorylation influences physico-chemical properties of proteins are described. In the first and the second chapter the evolution principles, function and regulation of protein kinases and phosphatases are provided. In the third chapter thesis concentrates on the distributions of phosphorylated sites among organisms (plants and animals). In the last chapter current knowledge of orthosteric and allosteric effects of phosphorylation as well as its effects on 2D and 3D structure of phosphorylated proteins is summarized.
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Computational study of short peptides and miniproteins in different environments
Vymětal, Jiří ; Vondrášek, Jiří (advisor) ; Svozil, Daniel (referee) ; Berka, Karel (referee)
Apart from biological functions, peptides are of uttermost importance as models for un- folded, denatured or disordered state of the proteins. Similarly, miniproteins such as Trp-cage have proven their role as simple models of both experimental and theoretical studies of protein folding. Molecular dynamics and computer simulations can provide an unique insight on processes at atomic level. However, simulations of peptides and minipro- teins face two cardinal problems-inaccuracy of force fields and inadequate conformation sampling. Both principal issues were tackled in this theses. Firstly, the differences in several force field for peptides and proteins were questioned. We demonstrated the inability of the used force fields to predict consistently intrinsic conformational preferences of individual amino acids in the form of dipeptides and the source of the discrepancies was traced. In order to shed light on the nature of conformational ensembles under various denatur- ing conditions, we studied host-guest AAXAA peptides. The simulations revealed that thermal and chemical denaturation by urea produces qualitatively different ensembles and shift propensities of individual amino acids to particular conformers. The problem of insufficient conformation sampling was dealt by introducing gyration- and...
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