Structure and function of the vacuolar H+-ATPase: moving from low-resolution models to high-resolution structures.
In the absence of a high-resolution structure for the vacuolar H+-ATPase, a number of approaches can yield valuable information about structure/function relationships in the enzyme. Electron microscopy can provide not only a representation of the overall architecture of the complex, but also a low-resolution map onto which structures solved for individually expressed subunits can be fitted. Here we review the possibilities for electron microscopy of the Saccharomyces V-ATPase and examine the suitability of V-ATPase subunits for expression in high yield prokaryotic systems, a key step towards high-resolution structural studies. We also review the role of experimentally-derived structural models in understanding structure/function relationships in the V-ATPase, with particular reference to the complex of proton-translocating 16 kDa proteolipids in the membrane domain of the V-ATPase. This model in turn makes testable predictions about the sites of binding of bafilomycins and the functional interactions between the proteolipid and the single-copy membrane subunit Vph1p, with implications for the constitution of the proton translocation pathway.
Harrison
Michael
M
School of Biochemistry and Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom. m.a.harrison@leeds.ac.uk
Durose
Lyndsey
L
Song
Chun Feng
CF
Barratt
Elizabeth
E
Trinick
John
J
Jones
Richard
R
Findlay
John B C
JB
D002462:Cell Membrane / Q000737:chemistry; D008958:Models, Molecular; D015394:Molecular Structure; D012995:Solubility; D025262:Vacuolar Proton-Translocating ATPases / Q000737:chemistry* / Q000502:physiology*
D025262:Vacuolar Proton-Translocating ATPases