1a3s
From Proteopedia
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HUMAN UBC9
Overview
The three-dimensional structure of ubiquitin-conjugating enzyme 9 (Ubc9), has been obtained to a resolution of 2.8 A by molecular replacement, followed by a combination of automated refinement and graphical, intervention. Diffraction data were recorded on a single crystal in space, group P43 with cell dimensions a = b = 73.9, c = 42. 9 A. The final model, has an R factor of 21.3% for all data to 2.8 A. Only the N-terminal, methionine, a two-residue N-terminal extension and a four-residue loop are, not located by the final electron-density map. Ubc9 is now known to be the, first sumo, a new ubiquitin-like protein, conjugating enzyme and does not, conjugate ubiquitin. The structure of Ubc9 shows important differences, compared with the structures of known ubiquitin-conjugating enzymes. At, the N-terminal helix, the structural and sequence alignments are out of, register by one amino acid giving Ubc9 a different recognition surface, compared to ubiquitin-conjugating enzymes. This is coupled to a profound, change in the electrostatic surface of the molecular face remote from the, catalytic site. These differences may be important in recognition of other, proteins in the Sumo conjugation pathway. The catalytic cysteine in Ubc9, has a positively charged lip and a negatively charged ridge nearby. Both, these features seem confined to sumo-conjugating enzymes, and a sequence, alignment of sumo and ubiquitin suggests how these might play a role in, sumo/ubiquitin discrimination.
About this Structure
1A3S is a Single protein structure of sequence from Homo sapiens. Active as Ubiquitin--protein ligase, with EC number 6.3.2.19 Full crystallographic information is available from OCA.
Reference
Structure of ubiquitin-conjugating enzyme 9 displays significant differences with other ubiquitin-conjugating enzymes which may reflect its specificity for sumo rather than ubiquitin., Giraud MF, Desterro JM, Naismith JH, Acta Crystallogr D Biol Crystallogr. 1998 Sep 1;54(Pt 5):891-8. PMID:9757105
Page seeded by OCA on Fri Feb 15 15:28:18 2008
