Structural basis for the reversibility of proton pyrophosphatase.
Proton Pyrophosphatase (H+-PPase) is an evolutionarily conserved enzyme regarded as a bona fide vacuolar marker. However, H+-PPase also localizes at the plasma membrane of the phloem, where, evidence suggests that it functions as a Pyrophosphate Synthase and participates in phloem loading and photosynthate partitioning. We believe that this pyrophosphate synthesising function of H+-PPase is fundamentally rooted to its molecular structure, and here we postulate, on the basis of published crystal structures of membrane-bound pyrophosphatases, a plausible mechanism of pyrophosphate synthesis.
a School of Life Sciences, Arizona State University , Tempe , AZ , USA.
Kamesh C
KC
Regmi
b Center for Research in Agricultural Genomics, Cerdanyola del Vallès , Barcelona , Spain.
Gaston A
GA
Pizzio
a School of Life Sciences, Arizona State University , Tempe , AZ , USA.
Roberto A
RA
Gaxiola
D002462:Cell Membrane / Q000378:metabolism; D043564:Inorganic Pyrophosphatase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D011755:Pyrophosphatases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
D010940:Plant Proteins; D011755:Pyrophosphatases; D043564:Inorganic Pyrophosphatase
Crystal structure; Proton pyrophosphatase; Pyrophosphate synthase; Sodium pyrophosphatase; Sodium/Proton pyrophosphatase