6hh0
From Proteopedia
Yeast V-ATPase transmembrane helix 7 NMR structure in DPC micelles
Structural highlights
FunctionVPP1_YEAST Subunit of the V0 complex of vacuolar(H+)-ATPase (V-ATPase), a multisubunit enzyme composed of a peripheral complex (V1) that hydrolyzes ATP and a membrane integral complex (V0) that translocates protons (PubMed:1491220, PubMed:8798414, PubMed:11278748). V-ATPase is responsible for acidifying and maintaining the pH of intracellular compartments (PubMed:1491220, PubMed:11278748). Is present only in vacuolar V-ATPase complexes; enzymes containing this subunit have a 4-fold higher ratio of proton transport to ATP hydrolysis than complexes containing the Golgi/endosomal isoform and undergo reversible dissociation of V1 and V0 in response to glucose depletion (PubMed:8798414, PubMed:11278748).[1] [2] [3] Publication Abstract from PubMedVacuolar ATPases are multisubunit protein complexes that are indispensable for acidification and pH homeostasis in a variety of physiological processes in all eukaryotic cells. An arginine residue (Arg-735) in transmembrane helix 7 (TM7) of subunit a of the yeast ATPase is known to be essential for proton translocation. However, the specific mechanism of its involvement in proton transport remains to be determined. Arginine residues are usually assumed to "snorkel" toward the protein surface when exposed to a hydrophobic environment. Here, using solution NMR spectroscopy, molecular dynamics simulations and in vivo yeast assays, we obtained evidence for the formation of a transient, membrane-embedded cation-pi interaction in TM7 between Arg-735 and two highly conserved nearby aromatic residues, Tyr-733 and Trp-737. We propose a mechanism by which the transient, membrane-embedded cation-pi complex provides the necessary energy to keep the charged side chain of Arg-735 within the hydrophobic membrane. Such cation-pi interactions may define a general mechanism to retain charged amino acids in a hydrophobic membrane environment. A cation-pi interaction in a transmembrane helix of vacuolar ATPase retains the proton transporting arginine in a hydrophobic environment.,Hohlweg W, Wagner GE, Hofbauer HF, Sarkleti F, Setz M, Gubensak N, Lichtenegger S, Falsone SF, Wolinski H, Kosol S, Oostenbrink C, Kohlwein SD, Zangger K J Biol Chem. 2018 Sep 12. pii: RA118.005276. doi: 10.1074/jbc.RA118.005276. PMID:30209131[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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