2FIF: Crystal Structure Of A Bovine Rabex-5 Fragment Complexed With Ubiquitin

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.
PDB ID: 2FIFDownload
MMDB ID: 37754
PDB Deposition Date: 2005/12/29
Updated in MMDB: 2012/11
Experimental Method:
x-ray diffraction
Resolution: 2.49  Å
Source Organism:
Similar Structures:
Biological Unit for 2FIF: dimeric; determined by author and by software (PISA)
Molecular Components in 2FIF
Label Count Molecule
Proteins (2 molecules)
Molecule annotation
Rab5 Gdp/gtp Exchange Factor(Gene symbol: RABGEF1)
Molecule annotation
Chemicals (2 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB