ยท
H-J. Yeo, S.N. Savvides, A.B. Herr, E. Lanka, and G. Waksman.
Crystal structure of the hexameric traffic ATPase of the Helicobacter pylori
type IV secretion system
Molecular Cell. 6:1461-1472. (2000)
The type IV secretion system of Helicobacter
pylori consists of 10-15
proteins responsible for transport of the transforming protein CagA into target
epithelial cells. Secretion of CagA depends on the hexameric ATPase, HP0525, a
member of the VirB11-PulE family. We present the crystal structure of a binary
complex of HP0525 bound to ADP. Each monomer consists of two domains formed by
the N- and C-terminal halves of the sequence. ADP is bound at the interface
between the two domains. In the hexamer, the N- and C-terminal domains form two
rings which together form a chamber open on one side and closed on the other. A
model for HP0525 function is proposed in which HP0525 works as an inner-
membrane protein usher, the closure and opening of which is regulated by ATP
binding and ADP release.