4sli
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(New page: 200px<br /><applet load="4sli" size="450" color="white" frame="true" align="right" spinBox="true" caption="4sli, resolution 1.8Å" /> '''LEECH INTRAMOLECULAR ...)
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Revision as of 17:41, 20 November 2007
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LEECH INTRAMOLECULAR TRANS-SIALIDASE COMPLEXED WITH 2-PROPENYL-NEU5AC, AN INACTIVE SUBSTRATE ANALOGUE
Overview
Intramolecular trans-sialidase from leech (Macrobdella decora) is the, first member of the sialidase superfamily found to exhibit strict, specificity towards the cleavage of terminal Neu5Acalpha2-->3Gal linkage, in sialoglycoconjugates. Its release of 2,7-anhydro-Neu5Ac instead of, Neu5Ac indicates that it catalyzes an intramolecular trans-sialosyl, reaction. Crystal structures of its complexes with an inactive substrate, analogue 2-propenyl-Neu5Ac, and with the product 2,7-anhydro-Neu5Ac, have, been determined to 1.8 A resolution. The boat conformation of the pyranose, observed in the complexes supports the proposed enzymatic mechanism that, O7 of an axial 6-glycerol group attacks the positively charged C2 of the, intermediate. A generalized mechanism is proposed for the sialidase, superfamily.
About this Structure
4SLI is a Single protein structure of sequence from Macrobdella decora with CNP as ligand. Active as Exo-alpha-sialidase, with EC number 3.2.1.18 Full crystallographic information is available from OCA.
Reference
The 1.8 A structures of leech intramolecular trans-sialidase complexes: evidence of its enzymatic mechanism., Luo Y, Li SC, Li YT, Luo M, J Mol Biol. 1999 Jan 8;285(1):323-32. PMID:9878409
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