PMID: 24316825

Authors:

Rimsa V, Eadsforth TC, Hunter WN

Title:

Two high-resolution structures of the human E3 ubiquitin ligase Siah1.

Journal:

Acta Crystallogr Sect F Struct Biol Cryst Commun. 2013 Dec;69(Pt 12):1339-43., doi: 10.1107/S1744309113031448. Epub 2013 Nov 28.

Abstract:

Siah1 is an E3 ubiquitin ligase that contributes to proteasome-mediated degradation of multiple targets in key cellular processes and which shows promise as a therapeutic target in oncology. Structures of a truncated Siah1 bound to peptide-based inhibitors have been reported. Here, new crystallization conditions have allowed the determination of a construct encompassing dual zinc-finger subdomains and substrate-binding domains at significantly higher resolution. Although the crystals appear isomorphous, two structures present distinct states in which the spatial orientation of one zinc-finger subdomain differs with respect to the rest of the dimeric protein. Such a difference, which is indicative of conformational freedom, infers potential biological relevance related to recognition of binding partners. The crystallization conditions and improved models of Siah1 may aid future studies investigating Siah1-ligand complexes.