6ap1
Vps4p-Vta1p complex with peptide binding to the central pore of Vps4p
Structural highlights
FunctionVTA1_YEAST Has a role in the formation of the multivesicular body (MVB). Required for the sorting of lipids to form intralumenal vesicles and for fluid-phase transport to the vacuole. Required for sorting the plasma membrane proteins STE2 and STE3 into the MVB. Acts a cofactor of VSP4, promotes the oligomerization of VPS4 and stimulates its ATPase activity by 6- to 8-fold.[1] [2] [3] [4] Publication Abstract from PubMedThe hexameric AAA ATPase Vps4 drives membrane fission by remodeling and disassembling ESCRT-III filaments. Building upon our earlier 4.3 A resolution cryo-EM structure (Monroe et al., 2017), we now report a 3.2 A structure of Vps4 bound to an ESCRT-III peptide substrate. The new structure reveals that the peptide approximates a beta-strand conformation whose helical symmetry matches that of the five Vps4 subunits it contacts directly. Adjacent Vps4 subunits make equivalent interactions with successive substrate dipeptides through two distinct classes of side chain binding pockets formed primarily by Vps4 pore loop 1. These pockets accommodate a wide range of residues, while main chain hydrogen bonds may help dictate substrate-binding orientation. The structure supports a 'conveyor belt' model of translocation in which ATP binding allows a Vps4 subunit to join the growing end of the helix and engage the substrate, while hydrolysis and release promotes helix disassembly and substrate release at the lagging end. The AAA ATPase Vps4 binds ESCRT-III substrates through a repeating array of dipeptide-binding pockets.,Han H, Monroe N, Sundquist WI, Shen PS, Hill CP Elife. 2017 Nov 22;6. doi: 10.7554/eLife.31324. PMID:29165244[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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