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Journal articles
Trypanosoma cruzi Trans-sialidase Operates through a Covalent Sialyl-Enzyme Intermediate: Tyrosine Is the Catalytic Nucleophile
Abstract : Modified sialic acid substrates have been used to label Trypanosoma cruzi trans-sialidase, demonstrating that the enzyme catalyses the transfer of sialic acid through a covalent glycosyl-enzyme intermediate, a mechanism common to most retaining glycosidases. Peptic digestion of labeled protein, followed by LC-MS/MS analysis of the digest, identified Tyr342 as the catalytic nucleophile. This is the first such example of a retaining glycosidase utilizing an aryl glycoside intermediate. It is suggested that this alternative choice of nucleophile is a consequence of the chemical nature of sialic acid. A Tyr/Glu couple is invoked to relay charge from a remote glutamic acid, thereby avoiding electrostatic repulsion with the sialic acid carboxylate group.
Cited literature [16 references]
https://hal-pasteur.archives-ouvertes.fr/pasteur-02554098
Contributor : Alejandro Buschiazzo <>
Submitted on : Friday, April 24, 2020 - 11:50:01 PM
Last modification on : Thursday, May 14, 2020 - 1:27:22 AM
Contributor : Alejandro Buschiazzo <>
Submitted on : Friday, April 24, 2020 - 11:50:01 PM
Last modification on : Thursday, May 14, 2020 - 1:27:22 AM
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