Structure of the rotor ring modified with N,N'-dicyclohexylcarbodiimide of the Na+-transporting vacuolar ATPase.

ABSTRACT: The prokaryotic V-ATPase of Enterococcus hirae, closely related to the eukaryotic enzymes, provides a unique opportunity to study the ion-translocation mechanism because it transports Na(+), which can be detected by radioisotope (22Na(+)) experiments and X-ray crystallography. In this study, we demonstrated that the binding affinity of the rotor ring (K ring) for 22Na(+) decreased approximately 30-fold by reaction with N,N(')-dicyclohexylcarbodiimide (DCCD), and determined the crystal structures of Na(+)-bound and Na(+)-unbound K rings modified with DCCD at 2.4- and 3.1-Å resolutions, respectively. Overall these structures were similar, indicating that there is no global conformational change associated with release of Na(+) from the DCCD-K ring. A conserved glutamate residue (E139) within

SUBMITTER: Mizutani K 

PROVIDER: S-EPMC3158168 | biostudies-literature | 2011 Aug

REPOSITORIES: biostudies-literature