Structure of a Sialic Acid-Activating Synthetase, CMP-acylneuraminate Synthetase in the Presence and Absence of CDP

J Biol Chem. 2001 Mar 16;276(11):8190-6. doi: 10.1074/jbc.M007235200. Epub 2000 Dec 11.

Abstract

The x-ray crystallographic structure of selenomethionyl cytosine-5'-monophosphate-acylneuraminate synthetase (CMP-NeuAc synthetase) from Neisseria meningitidis has been determined at 2.0-A resolution using multiple-wavelength anomalous dispersion phasing, and a second structure, in the presence of the substrate analogue CDP, has been determined at 2.2-A resolution by molecular replacement. This work identifies the active site residues for this class of enzyme for the first time. The detailed interactions between the enzyme and CDP within the mononucleotide-binding pocket are directly observed, and the acylneuraminate-binding pocket has also been identified. A model of acylneuraminate bound to CMP-NeuAc synthetase has been constructed and provides a structural basis for understanding the mechanism of production of "activated" sialic acids. Sialic acids are key saccharide components on the surface of mammalian cells and can be virulence factors in a variety of bacterial species (e.g. Neisseria, Haemophilus, group B streptococci, etc.). As such, the identification of the bacterial CMP-NeuAc synthetase active site can serve as a starting point for rational drug design strategies.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Binding Sites
  • Cytidine Diphosphate / chemistry*
  • Dimerization
  • Molecular Sequence Data
  • N-Acetylneuraminic Acid / metabolism*
  • N-Acylneuraminate Cytidylyltransferase / chemistry
  • Protein Conformation
  • Protein Folding
  • Protein Structure, Secondary

Substances

  • Cytidine Diphosphate
  • N-Acylneuraminate Cytidylyltransferase
  • N-Acetylneuraminic Acid

Associated data

  • PDB/1EYR
  • PDB/1EZI