Download MendeleyIncreasing loop flexibility affords low-temperature adaptation of a moderate thermophilic malate dehydrogenase from Geobacillus stearothermophilus.
Shimozawa, Y., Himiyama, T., Nakamura, T., Nishiya, Y.(2021) Protein Eng Des Sel 34
- PubMed: 34850194
- DOI: https://doi.org/10.1093/protein/gzab026
- Primary Citation of Related Structures:
7F8D - PubMed Abstract:
Malate dehydrogenase (MDH) catalyzes the reversible reduction of nicotinamide adenine dinucleotide from oxaloacetate to L-malate. MDH from moderate thermophilic Geobacillus stearothermophilus (gs-MDH) has high thermal stability and substrate specificity and is used as a diagnostic reagent. In this study, gs-MDH was engineered to increase its catalytic activity at low temperatures. Based on sequential and structural comparison with lactate dehydrogenase from G. stearothermophilus, we selected G218 as a mutation site to increase the loop flexibility pivotal for MDH catalysis. The G218 mutants showed significantly higher specific activities than the wild type at low temperatures and maintained thermal stability. The crystal structure of the G218Y mutant, which had the highest catalytic efficiency among all the G218 mutants, suggested that the flexibility of the mobile loop was successfully increased by the bulky side chain. Therefore, this study demonstrated the low-temperature adaptation of MDH by facilitating conformational changes during catalysis.
Organizational Affiliation:
Division of Life Science, Graduate School of Science and Engineering, Setsunan University, 17-8 Ikeda-Nakamachi, Neyagawa, Osaka 572-8508, Japan.
