2b3h
Crystal structure of Human Methionine Aminopeptidase Type I with a third cobalt in the active site
Structural highlights
FunctionMAP11_HUMAN Cotranslationally removes the N-terminal methionine from nascent proteins. The N-terminal methionine is often cleaved when the second residue in the primary sequence is small and uncharged (Met-Ala-, Cys, Gly, Pro, Ser, Thr, or Val). Required for normal progression through the cell cycle.[HAMAP-Rule:MF_03174][1] [2] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedDetermination of the crystal structure of human MetAP1 makes it possible, for the first time, to compare the structures of a Type I and a Type II methionine aminopeptidase (MetAP) from the same organism. Comparison of the Type I enzyme with the previously reported complex of ovalicin with Type II MetAP shows that the active site of the former is reduced in size and would incur steric clashes with the bound inhibitor. This explains why ovalicin and related anti-angiogenesis inhibitors target Type II human MetAP but not Type I. The differences in both size and shape of the active sites between MetAP1 and MetAP2 also help to explain their different substrate specificity. In the presence of excess Co(2+), a third cobalt ion binds in the active site region, explaining why metal ions in excess can be inhibitory. Also, the N-terminal region of the protein contains three distinct Pro-x-x-Pro motifs, supporting the prior suggestion that this region of the protein may participate in binding to the ribosome. Structural basis for the functional differences between type I and type II human methionine aminopeptidases.,Addlagatta A, Hu X, Liu JO, Matthews BW Biochemistry. 2005 Nov 15;44(45):14741-9. PMID:16274222[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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