Thiocyanate hydrolase is a cobalt-containing metalloenzyme with a cysteine-sulfinic acid ligand
Thiocyanate hydrolase is a cobalt-containing metalloenzyme with a cysteine-sulfinic acid ligand
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DOI：
10.1021/ja057010q
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发表时间：
2006-01-25
影响因子：
15
通讯作者：
Odaka, M
中科院分区：
文献类型：
--
作者：
Katayama, Y;Hashimoto, K;Odaka, M
从硫杆菌THI115 中纯化的硫氰酸水解酶（SCNase）可将硫氰酸水解为硫化羰和氨。克隆基因的DNA序列揭示了SCNase与腈水合酶(NHase)的密切关系。 NHase 中金属离子配位的共有序列在 SCNase 的 γ 亚基中也是保守的。在这里，我们证明 SCNase 的每个 αβγ 异三聚体含有一个钴原子。紫外可见吸收光谱表明钴以非咕啉离子形式存在。还原的 SCNase 显示出低自旋 Co2+ 的 ESR 信号特征，与 Co 型 NHase 非常相似。含有 SCNase γ 亚基金属结合基序的肽片段的质谱分析表明，131 位的半胱氨酸残基翻译后氧化为半胱氨酸亚磺酸。从这些结果中，我们得出结论，SCNases和NHases形成了具有翻译后修饰的半胱氨酸配体的新型非corrin和/或非血红素蛋白家族。
Thiocyanate hydrolase (SCNase) purified fromThiobacillus thioparusTHI115 hydrolyzes thiocyanate to carbonyl sulfide and ammonia. DNA sequences of the cloned genes revealed the close relation of SCNase to nitrile hydratase (NHase). The consensus sequences for coordination of the metal ion found in NHases were also conserved in the γ subunit of SCNase. Here, we showed that the SCNase contained one cobalt atom per αβγ heterotrimer. UV−vis absorption spectrum suggested that the cobalt exists as a non-corrin ion. Reduced SCNase showed an ESR signal characteristic of low-spin Co2+, which closely resembled that of the Co-type NHases. Mass spectrometry for the peptide fragment containing the metal-binding motif of the SCNase γ subunit indicated that the cysteine residue at position 131 was post-translationally oxidized to a cysteine-sulfinic acid. From these results, we concluded that SCNases and NHases form a novel non-corrin and/or non-heme protein family having post-translationally modified cysteine ligands.