Thiocyanate Hydrolase Is a Cobalt-Containing Metalloenzyme with a Cysteine-Sulfinic Acid Ligand
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- 作者：Yoko Katayama ; Kanako Hashimoto ; Hiroshi Nakayama ; Hiroyuki Mino ; Masaki Nojiri ; Taka-aki Ono ; Hiroshi Nyunoya ; Masafumi Yohda ; Koji Takio ; and Masafumi Odaka
- 刊名：Journal of the American Chemical Society
- 出版年：2006
- 出版时间：January 25, 2006
- 年：2006
- 卷：128
- 期：3
- 页码：728 - 729
- 全文大小：43K
- 年卷期：v.128,no.3(January 25, 2006)
- ISSN：1520-5126
文摘
Thiocyanate hydrolase (SCNase) purified from Thiobacillus thioparus THI115 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 
subunit of SCNase. Here, we showed that the SCNase contained one cobalt atom per 
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 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.
subunit of SCNase. Here, we showed that the SCNase contained one cobalt atom per 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 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.