Referenced in: none

Automatically associated channels: Kir2.3

Title: Structure of the rotor of the V-Type Na+-ATPase from Enterococcus hirae.

Authors: Takeshi Murata, Ichiro Yamato, Yoshimi Kakinuma, Andrew G W Leslie, John E Walker

Journal, date & volume: Science, 2005 Apr 29 , 308, 654-9

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/15802565

Abstract
The membrane rotor ring from the vacuolar-type (V-type) sodium ion-pumping adenosine triphosphatase (Na+-ATPase) from Enterococcus hirae consists of 10 NtpK subunits, which are homologs of the 16-kilodalton and 8-kilodalton proteolipids found in other V-ATPases and in F1Fo- or F-ATPases, respectively. Each NtpK subunit has four transmembrane alpha helices, with a sodium ion bound between helices 2 and 4 at a site buried deeply in the membrane that includes the essential residue glutamate-139. This site is probably connected to the membrane surface by two half-channels in subunit NtpI, against which the ring rotates. Symmetry mismatch between the rotor and catalytic domains appears to be an intrinsic feature of both V- and F-ATPases.