2sli
LEECH INTRAMOLECULAR TRANS-SIALIDASE COMPLEXED WITH 2,7-ANHYDRO-NEU5AC, THE REACTION PRODUCT
OverviewOverview
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 StructureAbout this Structure
2SLI is a Single protein structure of sequence from Macrobdella decora. Full crystallographic information is available from OCA.
ReferenceReference
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 Page seeded by OCA on Sun May 4 17:19:45 2008