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From Proteopedia
Solution structure of TM7 bound to 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 PubMedMany peptides, proteins, and drugs interact with biological membranes, and knowing the mode of binding is essential to understanding their biological functions. To obtain the complete orientation and immersion depth of such a compound, the membrane-mimetic system (micelle) is placed in an aqueous buffer containing the soluble and inert paramagnetic contrast agent Gd(DTPA-BMA). Paramagnetic relaxation enhancements (PREs) of a specific nucleus then depend only on its distance from the surface. The positioning of a structurally characterized compound can be obtained by least-squares fitting of experimental PREs to the micelle center position. This liquid-state NMR approach, which does not rely on isotopic labeling or chemical modification, has been applied to determine the location of the presumed transmembrane region 7 of yeast V-ATPase (TM7) and the membrane-bound antimicrobial peptide CM15 in micelles. TM7 binds in a trans-micelle orientation with the N-terminus being slightly closer to the surface than the C-terminus. CM15 is immersed unexpectedly deep into the micelle with the more hydrophilic side of the helix being closer to the surface than the hydrophobic one. Positioning of Micelle-Bound Peptides by Paramagnetic Relaxation Enhancements.,Zangger K, Respondek M, Gobl C, Hohlweg W, Rasmussen K, Grampp G, Madl T J Phys Chem B. 2009 Mar 3. PMID:19256533[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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