9llv | pdb_00009llv
Dimer Sgt2 from S.cerevisiae
Structural highlights
FunctionSGT2_YEAST Co-chaperone that binds to the molecular chaperone Hsp70 (SSA1 and SSA2). Regulates Hsp70 ATPase activity (By similarity). Required for recovery from heat shock.[1] Publication Abstract from PubMedWhile the regulation of protein function theoretically encompasses alterations in both structural conformation and dynamic properties, the latter aspect, specifically conformational entropy, remains relatively unexplored. Here we show that an intrinsically disordered region (IDR), a prominent component of the proteome, can remotely switch protein activity on or off through a nonbinding, entropy-driven mechanism. Focusing on the disordered C-terminal tail of Sgt2, a chaperone in the guided entry of tail-anchored protein pathway, we demonstrate that it allosterically inhibits the N-terminal domain without direct contact, preventing unproductive chaperone-chaperone interactions. This inhibition is relieved upon client binding. These effects depend on specific IDR sequences but not the intervening regions. Beyond acting as a relay signal, the IDR also forms a dynamic complex with transmembrane domains of tail-anchored clients, serving as an entropic shelter. Moreover, the IDR-mediated activity of Sgt2 correlates with fast internal dynamics, establishing conformational entropy as a key regulatory principle. Our findings reveal IDRs as two-way entropic modulators, enabling distant, on-demand activity switching. Remote on-off switching of protein activity by intrinsically disordered region.,Ji T, Ge P, Zhang S, Wan C, Liu H, Qu X, Zhu F, Gong Q, Xu W, Wang C, Wang Y, Huang C Nat Struct Mol Biol. 2025 Oct;32(10):2088-2098. doi: 10.1038/s41594-025-01585-7. , Epub 2025 Jun 4. PMID:40467883[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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