Structural dissection of the CMP-pseudaminic acid synthetase, PseF.

Pseudaminic acid is a non-mammalian sugar found in the surface glycoconjugates of many bacteria, including several human pathogens, and is a virulence factor thought to facilitate immune evasion. The final step in the biosynthesis of the nucleotide activated form of the sugar, CMP-Pse5Ac7Ac is performed by a CMP-Pse5Ac7Ac synthetase (PseF). Here we present the biochemical and structural characterization of PseF from Aeromonas caviae (AcPseF), with AcPseF displaying metal-dependent activity over a broad pH and temperature range.

The Retaining Pse5Ac7Ac Pseudaminyltransferase KpsS1 Defines a Previously Unreported glycosyltransferase family (GT118).

Cell surface sugar 5,7-diacetyl pseudaminic acid (Pse5Ac7Ac) is a bacterial analogue of the ubiquitous sialic acid, Neu5Ac, and contributes to the virulence of a number of multidrug resistant bacteria, including ESKAPE pathogens Pseudomonas aeruginosa, and Acinetobacter baumannii. Despite its discovery in the surface glycans of bacteria over thirty years ago, to date no glycosyltransferase enzymes (GTs) dedicated to the synthesis of a pseudaminic acid glycosidic linkage have been unequivocally characterised in vitro. Herein we demonstrate that A.

Co-factor prosthesis facilitates biosynthesis of azido-pseudaminic acid probes for use as glycosyltransferase reporters.

Truncated thioester ,-diacetylcysteamine (SNAc) was utilised as a co-factor mimic for PseH, an acetyl-coA dependent aminoglycoside -acetyltransferase, in the biosynthesis of the bacterial sugar, pseudaminic acid. Additionally, an azido-SNAc analogue was used to smuggle 7-azide functionality into the pseudaminic acid backbone, facilitating its use as a reporter of pseudaminyltransferase activity.