Double mutations far from the active site affect cold activity in an Antarctic halophilic β-galactosidase.

ABSTRACT: The Antarctic haloarchaeon, Halorubrum lacusprofundi, contains a polyextremophilic family 42 β-galactosidase, which we are using as a model for cold-active enzymes. Divergent amino acid residues in this 78 kDa protein were identified through comparative genomics and hypothesized to be important for cold activity. Six amino acid residues were previously mutated and five were shown by steady-state kinetic analysis to have altered temperature-dependent catalytic activity profiles via effects on K_m and/or k_cat compared to the wild-type enzyme. In this follow-up study, double-mutated enzymes were constructed and tested for temperature effects, including two new tandem residue pairs (N180T/A181T and T383A/S384A), and pairwise combination of the single residue mutations (N25

SUBMITTER: Laye VJ 

PROVIDER: S-EPMC8862438 | biostudies-literature | 2022 Mar

REPOSITORIES: biostudies-literature