2sli

Publication Abstract from PubMed

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.

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^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.