Structural studies on carbonyl sulfide hydrolase from Thiobacillus thioparus strain THI115

羰基硫化物是一种大气微量气体，导致硫酸盐气溶胶的形成，从而参与全球辐射平衡和臭氧化学。本研究通过测定硫代硫杆菌THI115中羰基硫水解酶（COSase）的晶体结构，阐明其底物识别机制。虽然包括催化位点在内的整体结构与β-类碳酸酐酶相似，但COSase的α5螺旋使其底物通路变窄，这可能是底物特异性的原因。

Carbonyl sulfide is an atmospheric trace gas leading to sulfate aerosol formation, thereby participating in the global radiation balance and ozone chemistry. In this study, the crystal structure of carbonyl sulfide hydrolase (COSase) from Thiobacillus thioparus strain THI115 was determined to clarify its substrate recognition mechanism. Althoughthe overall structure including the catalytic site resembles those of the β-classcarbonic anhydrases, the α5 helix of COSase narrows its substrate pathway, which couldbe responsible for the substrate specificity.