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Publication Abstract from PubMed

The major virulence factor of the neuroinvasive pathogen Escherichia coli K1 is the K1 capsule composed of alpha2,8-linked polysialic acid (polySia). K1 strains harboring the CUS-3 prophage modify their capsular polysaccharide by phase-variable O-acetylation, a step that is associated with increased virulence. Here we present the crystal structure of the prophage-encoded polysialate O-acetyltransferase NeuO. The homotrimeric enzyme belongs to the left-handed beta-helix (LbetaH) family of acyltransferases and is characterized by an unusual funnel-shaped outline. Comparison with other members of the LbetaH family allowed the identification of active site residues and proposal of a catalytic mechanism and highlighted structural characteristics of polySia specific O-acetyltransferases. As a unique feature of NeuO, the enzymatic activity linearly increases with the length of the N-terminal poly-psi-domain which is composed of a variable number of tandem copies of an RLKTQDS heptad. Since the poly-psi-domain was not resolved in the crystal structure it is assumed to be unfolded in the apo-enzyme.

Crystal structure analysis of the polysialic acid specific O-acetyltransferase NeuO.,Schulz EC, Bergfeld AK, Ficner R, Muhlenhoff M PLoS One. 2011 Mar 1;6(3):e17403. PMID:21390252^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.