3sli
LEECH INTRAMOLECULAR TRANS-SIALIDASE COMPLEXED WITH 2,7-ANHYDRO-NEU5AC PREPARED BY SOAKING WITH 3'-SIALYLLACTOSE
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| , resolution 1.8Å | |||||||
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| Ligands: | |||||||
| Gene: | T7 (Macrobdella decora) | ||||||
| Activity: | Exo-alpha-sialidase, with EC number 3.2.1.18 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
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
3SLI 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
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