2fid
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Crystal Structure of a Bovine Rabex-5 fragment complexed with ubiquitin
OverviewOverview
Rabex-5 is an exchange factor for Rab5, a master regulator of endosomal, trafficking. Rabex-5 binds monoubiquitin, undergoes covalent, ubiquitination and contains an intrinsic ubiquitin ligase activity, all of, which require an N-terminal A20 zinc finger followed immediately by a, helix. The structure of the N-terminal portion of Rabex-5 bound to, ubiquitin at 2.5-A resolution shows that Rabex-5-ubiquitin interactions, occur at two sites. The first site is a new type of ubiquitin-binding, domain, an inverted ubiquitin-interacting motif, which binds with, approximately 29-microM affinity to the canonical Ile44 hydrophobic patch, on ubiquitin. The second is a diaromatic patch on the A20 zinc finger, which binds with approximately 22-microM affinity to a polar region, centered on Asp58 of ubiquitin. The A20 zinc-finger diaromatic patch, mediates ubiquitin-ligase activity by directly recruiting a, ubiquitin-loaded ubiquitin-conjugating enzyme.
About this StructureAbout this Structure
2FID is a Protein complex structure of sequences from Bos taurus with ZN as ligand. Full crystallographic information is available from OCA.
ReferenceReference
Structural basis for ubiquitin recognition and autoubiquitination by Rabex-5., Lee S, Tsai YC, Mattera R, Smith WJ, Kostelansky MS, Weissman AM, Bonifacino JS, Hurley JH, Nat Struct Mol Biol. 2006 Mar;13(3):264-71. Epub 2006 Feb 5. PMID:16462746
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