Structure of AMP-PNP-bound BtuCD and mechanism of ATP-powered vitamin B12 transport by BtuCD-F.

Vladimir M Korkhov, Samantha A Mireku, Dmitry B Veprintsev, Kaspar P Locher

Index: Nat. Struct. Mol. Biol. 21(12) , 1097-9, (2014)

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Abstract

The reaction mechanism of BtuCD-F-catalyzed vitamin B12 transport into Escherichia coli is currently unclear. Here we present the structure of the last missing state in the form of AMP-PNP-bound BtuCD, trapped by a disulfide cross-link. Our structural and biochemical data allow a consistent mechanism to be formulated, thus rationalizing the roles of substrate, ATP and substrate-binding protein.