Dissecting and Engineering Allosteric Activation in a Biosynthetic Enzyme

ended

"Allosteric regulation of enzyme catalysis is widespread in nature and presents challenges and opportunities in synthetic biology. The enzyme ATP-phosphoribosyltransferase (ATPPRT) catalyses the first step in histidine biosynthesis, and is subject to complex allosteric inhibition by histidine. The short form of the enzyme, HisGS, is found in complex with a regulatory protein, HisZ. Such regulatory protein has a dual function: it allosterically enhances catalysis by HisGS, and it binds histidine and therefore mediates allosteric inhibition. The scientific aim of ""DEAllAct"" is to explore the design of a computational framework by combining state-of-the-art EVB/MM computational simulations and biophysical experimental studies to discover specific mutations at the protein-protein interface between HisGS and HisZ, that directly impact the transmission mechanism of the allosteric regulation. The fellow, Marina Corbella will carry out the project in Uppsala University under the supervision of Prof. Lynn Kamerlin who has extensive experience in computational chemistry and enzyme evolution. The first goal of ""DEAllAct"" is to elucidate the molecular details of the catalytic process of HisGS in the absence/presence of the regulatory protein HisZ via molecular dynamics simulations. Based on the information extracted from these simulations, a novel simulation tool will be developed to predict residues of key importance for binding interactions between the enzyme and the regulatory protein. Finally, the fellow will undergo a secondment at the University of St Andrews to test the hypothesis experimentally by introducing gain-of-function mutations on HisGS at the protein-protein interface to mimic the allosteric activation. Altogether, ""DEAllAct"" will provide the fellow with a highly competitive multidisciplinary profile by complementing her previous acquired expertise, putting her in a strong position to initiate her career as an independent and innovative research leader."