期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2018
卷号：115
期号：27
页码：7045-7050
DOI：10.1073/pnas.1801955115
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Ni-Fe clusters are inserted into the large subunit of [NiFe] hydrogenases by maturation proteins such as the Ni chaperone HypA via an unknown mechanism. We determined crystal structures of an immature large subunit HyhL complexed with HypA from Thermococcus kodakarensis . Structure analysis revealed that the N-terminal region of HyhL extends outwards and interacts with the Ni-binding domain of HypA. Intriguingly, the C-terminal extension of immature HyhL, which is cleaved in the mature form, adopts a β-strand adjacent to its N-terminal β-strands. The position of the C-terminal extension corresponds to that of the N-terminal extension of a mature large subunit, preventing the access of endopeptidases to the cleavage site of HyhL. These findings suggest that Ni insertion into the active site induces spatial rearrangement of both the N- and C-terminal tails of HyhL, which function as a key checkpoint for the completion of the Ni-Fe cluster assembly.
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