Thioredoxin-like protein TlpA from Bradyrhizobium japonicum is a reductant for the copper metallochaperone ScoI

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• 作者：Elisabeth Mohorko^a ; Helge K. Abicht^b ; Doris B&uuml ; hler^b ; Rudi Glockshuber^a ; Hauke Hennecke^b ; ^{hennecke@micro.biol.ethz.ch} ; Hans-Martin Fischer^b
• 关键词：Ccm ; cytochrome c maturation ; CoxII ; cytochrome oxidase subunit II ; DsbA ; disulfide bond-forming protein ; DTNB ; 5 ; 5&prime ; -dithio-bis(2-nitrobenzoic acid) ; DTT ; dithiothreitol ; EDTA ; ethylenediaminetetraacetate ; MALDI-MS ; matrix-assisted laser desorption/
• 刊名：FEBS Letters
• 出版年：2012
• 出版时间：30 November, 2012
• 年：2012
• 卷：586
• 期：23
• 页码：4094-4099
• 全文大小：1062 K

文摘

TlpA and ScoI of Bradyrhizobium japonicum are membrane-anchored thioredoxin-like proteins oriented towards the periplasm. TlpA is a protein-disulfide reductase. ScoI is a copper chaperone for cytochrome oxidase biogenesis. TlpA with its negative redox potential (E^o¡ä ?256 mV) was shown here to reduce oxidized ScoI, for which we determined a less negative E^o¡ä (?160 mV). The fast forward reaction (rate constant 9.4 ¡Á 10⁴ M^?1 s^?1) was typical for physiologically relevant disulfide exchange reactions. A transient TlpA-ScoI heterodisulfide formed between Cys107 of TlpA¡¯s active site (C₁₀₇XXC₁₁₀) and Cys78 of ScoI¡¯s copper-binding site (C₇₄XXXC₇₈). We conclude that TlpA recycles ScoI to the dithiol form prior to metallation.

Structured summary of protein interactions

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