Biochemistry Commons^™

Understanding The Molecular Mechanism Underlying The Great Thermal Stability Of Thermophilic Enzymes Using Aminoglycoside Nucleotidyltransferase 4' As A Model, Xiaomin Jing

Doctoral Dissertations

The aminoglycoside nucleotidyltransferase 4' (ANT) is a homodimeric enzyme that detoxifies antibiotics by nucleotidylating at the C4'-OH site. Two thermostable variants T130K and D80Y generated by direct evolution in laboratory differ by only a single residue replacement compared to the wild type mesophilic enzyme. Both variants display enhanced melting temperatures and execute catalysis at temperatures the wild type would be inactive. However, T130K variant still keeps molecular properties of mesophilic enzyme. T130àK130 does not trigger significant change in enzyme’s local flexibility or thermodynamics of ligand binding while D80Y variant has distinct properties in ligand recognition and dynamics. We hypothesize that …