Stepwise Enhancement of Catalytic Performance of Haloalkane Dehalogenase LinB towards β-Hexachlorocyclohexane
Moriuchi, R., Tanaka, H., Nikawadori, Y., Ishitsuka, M., Ito, M., Ohtsubo, Y., Tsuda, M., Damborsky, J., Prokop, Z., Nagata, Y.
APPLIED MICROBIOLOGY AND BIOTECHNOLOGY EXPRESS 4: 72 (2014)
Two haloalkane dehalogenases, LinBUT and LinBMI, each with 296 amino acid (aa) residues, exhibit only seven amino acid residue differences between them, but LinBMI‘s catalytic performance towards β-hexachlorocyclohexane (β-HCH) is considerably higher than LinBUT‘s. To elucidate the molecular basis governing this difference, intermediate mutants between LinBUT and LinBMI were constructed and kinetically characterized. The activities of LinBUT-based mutants gradually increased by cumulative mutations into LinBUT, and the effects of the individual amino acid substitutions depended on combination with other mutations. These results indicated that LinBUT‘s b-HCH degradation activity can be enhanced in a stepwise manner by the accumulation of point mutations.