Dynamic nature of disulphide bond formation catalysts revealed by crystal structures of DsbB |
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| Authors: | Kenji Inaba Satoshi Murakami Atsushi Nakagawa Hiroka Iida Mai Kinjo Koreaki Ito Mamoru Suzuki |
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| Institution: | 1. Division of Protein Chemistry, Post‐Genome Science Center, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan;2. Department of Life Science, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama, Japan;3. Institute for Protein Research, Osaka University, Osaka, Japan;4. Institute for Virus Research, Kyoto University and CREST, Japan Science and Technology Agency, Kyoto, Japan |
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| Abstract: | In the Escherichia coli system catalysing oxidative protein folding, disulphide bonds are generated by the cooperation of DsbB and ubiquinone and transferred to substrate proteins through DsbA. The structures solved so far for different forms of DsbB lack the Cys104–Cys130 initial‐state disulphide that is directly donated to DsbA. Here, we report the 3.4 Å crystal structure of a DsbB–Fab complex, in which DsbB has this principal disulphide. Its comparison with the updated structure of the DsbB–DsbA complex as well as with the recently reported NMR structure of a DsbB variant having the rearranged Cys41–Cys130 disulphide illuminated conformational transitions of DsbB induced by the binding and release of DsbA. Mutational studies revealed that the membrane‐parallel short α‐helix of DsbB has a key function in physiological electron flow, presumably by controlling the positioning of the Cys130‐containing loop. These findings demonstrate that DsbB has developed the elaborate conformational dynamism to oxidize DsbA for continuous protein disulphide bond formation in the cell. |
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| Keywords: | crystal structure analysis disulphide bond DsbA DsbB membrane protein |
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