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| Enzyme Name | | Swiss-prot | KEGG |
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| Q27701 |
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| Protein name | Anhydrosialidase | anhydrosialidaseanhydroneuraminidasesialglycoconjugate N-acylneuraminylhydrolase (2,7-cyclizing)sialidase L |
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| Synonyms | EC 4.2.2.15Sialidase LAnhydroneuraminidase |
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| Swiss-prot:Accession Number | Q27701 |
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| Entry name | NANL_MACDE |
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| Activity | Elimination of alpha-sialyl groups in N- acetylneuraminic acid glycosides, releasing 2,7-anhydro-alpha-N- acetylneuraminate. |
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| Subunit |
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| Subcellular location | Secreted, extracellular space. |
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| Cofactor |
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| References for Catalytic Mechanism | | References | Sections | No. of steps in catalysis |
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| [2] | Fig.4, p.526-528 |
| | [4] | Fig.5, p.326-329 |
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| references | | [1] |
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| PubMed ID | 2254319 |
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| Journal | J Biol Chem |
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| Year | 1990 |
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| Volume | 265 |
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| Pages | 21629-33 |
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| Authors | Li YT, Nakagawa H, Ross SA, Hansson GC, Li SC |
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| Title | A novel sialidase which releases 2,7-anhydro-alpha-N-acetylneuraminic acid from sialoglycoconjugates. |
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| [2] |
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| Comments | X-RAY CRYSTALLOGRAPHY (2.0 ANGSTROMS) OF 81-759. |
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| PubMed ID | 9562562 |
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| Journal | Structure |
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| Year | 1998 |
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| Volume | 6 |
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| Pages | 521-30 |
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| Authors | Luo Y, Li SC, Chou MY, Li YT, Luo M |
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| Title | The crystal structure of an intramolecular trans-sialidase with a NeuAc alpha2-->3Gal specificity. |
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| Related PDB | 1sli,1sll |
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| Related Swiss-prot | Q27701 |
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| [3] |
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| PubMed ID | 10513893 |
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| Journal | Biosci Rep |
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| Year | 1999 |
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| Volume | 19 |
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| Pages | 163-8 |
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| Authors | Sonnino S, Brocca P, Acquotti D, Bernardi A, Raimondi L, Kiso M, Ishida H, Li SC, Li YT |
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| Title | The structural basis for the susceptibility of gangliosides to enzymatic degradation. |
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| [4] |
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| Comments | X-RAY CRYSTALLOGRAPHY (1.8 ANGSTROMS) OF 81-759. |
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| PubMed ID | 9878409 |
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| Journal | J Mol Biol |
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| Year | 1999 |
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| Volume | 285 |
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| Pages | 323-32 |
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| Authors | Luo Y, Li SC, Li YT, Luo M |
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| Title | The 1.8 A structures of leech intramolecular trans-sialidase complexes: evidence of its enzymatic mechanism. |
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| Related PDB | 2sli,3sli,4sli |
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| Related Swiss-prot | Q27701 |
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| comments | According to the literature [2] & [4], this enzyme catalyzes intramolecular transfer of glycosyl group. The reaction proceeds by SN1 mechanism, as follows:
(1) Tyr713 acts as a modulator, polarizing the C2-O2 bond.
(2) Asp318 may act as a general acid to protonate the leaving O2 atom (probably through a water).
(3) The departure of the leaving group leads to the oxocarbonium intermediate with a positive charge formed on C2 atom, which is stabilized by Asp318 and Glu595.
(4) Asp318 acts as a general base, to activate the incoming hydroxyl O7 atom of grycerol group.
(5) The activated O7 atom makes a nucleophilic attack on the C2 atom to complete the reaction.
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| created | updated |
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| 2005-04-18 | 2009-02-26 |
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