Engineering Site 228 of Streptomyces coelicolor Laccase for Optimizing Catalytic Activity

• DOI: 10.1021/acs.jafc.4c00189
• Publication Date: 2024-03-06T20:45:26Z
• Authors: Luyao Bian; Silu Zhang; Tingting Chang; Jiacheng Zhang; Chong Zhang
• Keywords: Enzyme Kinetics; Protein Engineering; Saturated mutagenesis; Wild type

Malachite green (MG) poses a formidable threat to ecosystems and human health. Laccase emerges as promising candidate for MG degradation, prompting an investigation into the catalytic activity modulation of small laccase (SLAC) from Streptomyces coelicolor, with focus on amino acid position 228. Through saturation mutagenesis, five mutants 50% increase in specific were generated. Characterization revealed notable properties, Km E228F was 8.8% wild type (WT), E288T exhibited 133% kcat compared WT. Structural analyses indicated improved hydrophobicity electrostatic potential mutants' surfaces, stable E228F–ABTS complex exhibiting reduced flexibility, possibly contributing observed decrease turnover rate. Mutants demonstrated enhanced decolorization, particularly E228G. Site 228 acts crucial functional control switch, suggesting its role SLAC engineering. This study provides insights offers avenues enzymatic bioremediation applications.