1ofi
From Proteopedia
Asymmetric complex between HslV and I-domain deleted HslU (H. influenzae)
Structural highlights
Function[HSLU_HAEIN] ATPase subunit of a proteasome-like degradation complex; this subunit has chaperone activity. The binding of ATP and its subsequent hydrolysis by HslU are essential for unfolding of protein substrates subsequently hydrolyzed by HslV. HslU recognizes the N-terminal part of its protein substrates and unfolds these before they are guided to HslV for hydrolysis. [HSLV_HAEIN] Protease subunit of a proteasome-like degradation complex believed to be a general protein degrading machinery.[HAMAP-Rule:MF_00248] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedIn the prokaryotic homolog of the eukaryotic proteasome, HslUV, the "double donut" HslV protease is allosterically activated by HslU, an AAA protein of the Clp/Hsp100 family consisting of three (amino-terminal, carboxy-terminal, and intermediate) domains. The intermediate domains of HslU, which extend like tentacles from the hexameric ring formed by the amino-terminal and carboxy-terminal domains, have been deleted; an asymmetric HslU(DeltaI)(6)HslV(12) complex has been crystallized; and the structure has been solved to 2.5A resolution, revealing an assembly in which a HslU(DeltaI) hexamer binds one end of the HslV dodecamer. The conformation of the protomers of the HslU(DeltaI)-complexed HslV hexamer is similar to that in the symmetric wild-type HslUV complex, while the protomer conformation of the uncomplexed HslV hexamer is similar to that of HslV alone. Reaction in the crystals with a vinyl sulfone inhibitor reveals that the HslU(DeltaI)-complexed HslV hexamer is active, while the uncomplexed HslV hexamer is inactive. These results confirm that HslV can be activated by binding of a hexameric HslU(DeltaI)(6) ring lacking the I domains, that activation is effected through a conformational change in HslV rather than through alteration of the size of the entry channel into the protease catalytic cavity, and that the two HslV(6) rings in the protease dodecamer are activated independently rather than cooperatively. Structure and reactivity of an asymmetric complex between HslV and I-domain deleted HslU, a prokaryotic homolog of the eukaryotic proteasome.,Kwon AR, Kessler BM, Overkleeft HS, McKay DB J Mol Biol. 2003 Jul 4;330(2):185-95. PMID:12823960[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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