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Publication Abstract from PubMed

We used the Legionella pneumophila effector SidK to affinity purify the endogenous vacuolar-type ATPases (V-ATPases) from lemon fruit. The preparation was sufficient for cryoelectron microscopy, allowing structure determination of the enzyme in two rotational states. The structure defines the ATP:H(+) ratio of the enzyme, demonstrating that it can establish a maximum DeltapH of approximately 3, which is insufficient to maintain the low pH observed in the vacuoles of juice sac cells in lemons and other citrus fruit. Compared with yeast and mammalian enzymes, the membrane region of the plant V-ATPase lacks subunit f and possesses an unusual configuration of transmembrane alpha helices. Subunit H, which inhibits ATP hydrolysis in the isolated catalytic region of V-ATPase, adopts two different conformations in the intact complex, hinting at a role in modulating activity in the intact enzyme.

Structure of V-ATPase from citrus fruit.,Tan YZ, Keon KA, Abdelaziz R, Imming P, Schulze W, Schumacher K, Rubinstein JL Structure. 2022 Oct 6;30(10):1403-1410.e4. doi: 10.1016/j.str.2022.07.006. Epub , 2022 Aug 29. PMID:36041457^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.