4SLI

LEECH INTRAMOLECULAR TRANS-SIALIDASE COMPLEXED WITH 2-PROPENYL-NEU5AC, AN INACTIVE SUBSTRATE ANALOGUE

Summary for 4SLI

• Entry DOI: 10.2210/pdb4sli/pdb
• Descriptor: INTRAMOLECULAR TRANS-SIALIDASE, 2-propenyl-N-acetyl-neuraminic acid (3 entities in total)
• Functional Keywords: enzyme, intramolecular trans-sialidase
• Biological source: Macrobdella decora (North American leech)
• Cellular location: Secreted, extracellular space: Q27701
• Total number of polymer chains: 1
• Total formula weight: 74899.02

Authors

Luo, Y.,Li, S.C.,Li, Y.T.,Luo, M. (deposition date: 1998-10-04, release date: 1999-05-25, Last modification date: 2024-04-03)

Primary citation

Luo, Y.,Li, S.C.,Li, Y.T.,Luo, M.
The 1.8 A structures of leech intramolecular trans-sialidase complexes: evidence of its enzymatic mechanism.
J.Mol.Biol., 285:323-332, 1999

PubMed Abstract: 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.

PubMed: 9878409
DOI: 10.1006/jmbi.1998.2345

Experimental method

X-RAY DIFFRACTION (1.8 Å)