2ucz
From Proteopedia
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UBIQUITIN CONJUGATING ENZYME (UBC7) FROM SACCHAROMYCES CEREVISIAE
Overview
Ubiquitin-conjugating enzymes are a family of related proteins that, participate in the ubiquitination of proteins. Previous studies on the, crystal structures of Saccharomyces cerevisiae Ubc4 and Arabidopsis, thaliana Ubc1 indicated that the smallest enzymes (class I), which consist, entirely of the conserved core domain, share a common tertiary fold. Here, we report the three-dimensional structure of the S. cerevisiae class I, enzyme encoded by the UBC7 gene. The crystal structure has been solved, using molecular replacement techniques and refined by simulated annealing, to an R-factor of 0.183 at 2.93 A resolution. Bond lengths and angles in, the molecule have root-mean-square deviations from ideal values of 0.016 A, and 2.3 degrees, respectively. Ubc7 is an alpha/beta protein with four, alpha-helices and a four-stranded antiparallel beta-sheet. With the, exception of two regions where extra residues are present, the tertiary, folding of Ubc7 is similar to those of the other two enzymes. The, ubiquitin-accepting cysteine is located in a cleft between two loops. One, of these loops is nonconserved, as this region of the Ubc7 molecule, differs from the other two enzymes by having 13 extra residues. There is, also a second single amino acid insertion that alters the orientation of, the turn between the first two beta-strands. Analysis of the 13, ubiquitin-conjugating enzyme sequences in S. cerevisiae indicates that, there may be two other regions where extra residues could be inserted into, the common tertiary fold. Both of these other regions exhibit significant, deviations in the superposition of the three structures and, like the two, insertion regions in Ubc7, may represent hypervariable regions within a, common tertiary fold. As ubiquitin-conjugating enzymes interact with, different substrates or other accessory proteins in the ubiquitination, pathway, these variable surface regions may confer distinct specificity to, individual enzymes.
About this Structure
2UCZ is a Single protein structure of sequence from Saccharomyces cerevisiae. This structure superseeds the now removed PDB entry 1UCZ. Active as Ubiquitin--protein ligase, with EC number 6.3.2.19 Known structural/functional Site: . Full crystallographic information is available from OCA.
Reference
Crystal structure of a class I ubiquitin conjugating enzyme (Ubc7) from Saccharomyces cerevisiae at 2.9 angstroms resolution., Cook WJ, Martin PD, Edwards BF, Yamazaki RK, Chau V, Biochemistry. 1997 Feb 18;36(7):1621-7. PMID:9048545
Page seeded by OCA on Tue Dec 18 20:15:24 2007
