Fungal Carbonyl Sulfide Hydrolase of Trichoderma harzianum Strain THIF08 and Its Relationship with Clade D β-Carbonic Anhydrases.
Fungal Carbonyl Sulfide Hydrolase of Trichoderma harzianum Strain THIF08 and Its Relationship with Clade D β-Carbonic Anhydrases.
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DOI：
10.1264/jsme2.me20058
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发表时间：
2021
影响因子：
2.2
通讯作者：
Katayama Y
中科院分区：
文献类型：
--
作者：
Masaki Y;Iizuka R;Kato H;Kojima Y;Ogawa T;Yoshida M;Matsushita Y;Katayama Y
羰基硫化物（COS）是大气中含量最多、寿命最长的含硫气体。土壤是大气中COS的主要汇，其吸收主要由土壤微生物控制；然而，真菌对COS的降解尚未进行生化研究。从哈茨木霉（Trichoderma harzium）菌株THIF08中纯化COS水解酶（COSase），并克隆了COS基因（492 bp）。从大肠杆菌中纯化的表达cos基因的重组蛋白将cos转化为H2S。在β-碳酸酐酶（β-CA）家族系统进化树中，COSase的氨基酸序列（163个氨基酸）归属于D支，原核COSase及其结构相关酶均属于该家族。然而，菌株THIF08的COSase与之前已知的原核COSase及其相关酶不同，因为它对CO2的反应性较低，不能水解CS2。D支β-CA家族酶的活性位点氨基酸序列比较表明，各种子囊菌，特别是sordariomytes和eurotiomytes，与菌株THIF08的COSase具有相似的酶，同源性为>80%。这些真菌COSase在系统发育上与原核进化支D β-CA家族酶距离较远。这些结果表明，含有COS酶的各种子囊菌对土壤对COS的吸收有一定的促进作用。
Carbonyl sulfide (COS) is the most abundant and long-lived sulfur-containing gas in the atmosphere. Soil is the main sink of COS in the atmosphere and uptake is dominated by soil microorganisms; however, biochemical research has not yet been conducted on fungal COS degradation. COS hydrolase (COSase) was purified from Trichoderma harzianum strain THIF08, which degrades COS at concentrations higher than 10,000 parts per million by volume from atmospheric concentrations, and its gene cos (492 bp) was cloned. The recombinant protein purified from Escherichia coli expressing the cos gene converted COS to H2S. The deduced amino acid sequence of COSase (163 amino acids) was assigned to clade D in the phylogenetic tree of the β-carbonic anhydrase (β-CA) family, to which prokaryotic COSase and its structurally related enzymes belong. However, the COSase of strain THIF08 differed from the previously known prokaryotic COSase and its related enzymes due to its low reactivity to CO2 and inability to hydrolyze CS2. Sequence comparisons of the active site amino acids of clade D β-CA family enzymes suggested that various Ascomycota, particularly Sordariomycetes and Eurotiomycetes, possess similar enzymes to the COSase of strain THIF08 with >80% identity. These fungal COSase were phylogenetically distant to prokaryotic clade D β-CA family enzymes. These results suggest that various ascomycetes containing COSase contribute to the uptake of COS by soil.