Mechanism of proton pumping by plant plasma membrane H+-ATPase: role of residues in transmembrane segments 5 and 6.
The mechanism of proton pumping by P-type plasma membrane H(+)-ATPases is not well clarified. Site-directed mutagenesis studies suggest that Asp684, situated in transmembrane segment M6, is involved in coordination of proton(s) in plant plasma membrane H(+)-ATPase. This hypothesis is supported by atomic models of H(+)-ATPases built on the basis of the crystal structure of the related SERCA1a Ca(2+)-ATPase. However, more biochemical, genetic, and structural studies are required before we will be able to understand the nature of the proton binding site(s) in P-type H(+)-ATPases and the mechanism of action of these pumps.
Palmgren
M G
MG
Department of Plant Biology, The Royal Veterinary and Agricultural University, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark. palmgren@biobase.dk
Buch-Pedersen
M J
MJ
Møller
A L
AL
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology; D000252:Calcium-Transporting ATPases / Q000737:chemistry; D002462:Cell Membrane / Q000201:enzymology*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D006180:Proton-Translocating ATPases / Q000737:chemistry* / Q000378:metabolism*; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D006180:Proton-Translocating ATPases; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D000252:Calcium-Transporting ATPases