Molekulární mechanismus regulace funkce neutrální trehalasy Nth1

• Main Author: Kopecká, Miroslava
• Other Authors: Obšilová, Veronika
• Format: Doctoral Thesis
• Language: Czech
• Published: 2015
• Online Access: http://www.nusl.cz/ntk/nusl-352271

The yeast enzyme neutral trehalase (Nth1, EC 3.2.1.28) from the Saccharomyces cerevisiae helps these organisms to survive adverse living conditions. Nth1 hydrolyses a storage and protective disaccharide trehalose into two molecules of glucose. The activity of this enzyme is regulated by PKA phosphorylation, Ca2+ binding and the yeast 14-3-3 protein (Bmh1) binding. Ca2+ binds to the Ca-binding domain located within N-terminus of Nth1 and contains so called EF-hand motif (D114 TDKNYQITIED125 ) which is highly conserved among many Ca-binding proteins. The main aim of this project was to reveal the structural basis of the Bmh1- and calcium-dependent activation of Nth1. Other goals were to solve the structure of Nth1 itself and the structure of its complex with Bmh1. To reveal how the calcium regulates the Nth1 activity we prepared twelve mutant forms of Nth1 using site directed mutagenesis. These mutations were located within the region of EF-hand motif and its close vicinity. We estimated the enzymatic activity of all these mutants in the presence of Bmh1 and/or Ca2+ . The ability of Nth1 to form stable complexes with Bmh1 was verified using the native polyacrylamide gel electrophoresis and analytical ultracentrifugation. The impact of mutations on the structure and properties of Nth1 was tested using...