title: Crystal structures of N-acetylmannosamine kinase provide insights into enzyme activity and inhibition.
abstract: Sialic acids are essential components of membrane glycoconjugates. They are responsible for the interaction, structure, and functionality of all deuterostome cells and have major functions in cellular processes in health and diseases. The key enzyme of the biosynthesis of sialic acid is the bifunctional UDP-N-acetylglucosamine-2-epimerase/N-acetylmannosamine kinase that transforms UDP-N-acetylglucosamine to N-acetylmannosamine (ManNAc) followed by its phosphorylation to ManNAc 6-phosphate and has a direct impact on the sialylation of cell surface components. Here, we present the crystal structures of the human N-acetylmannosamine kinase (MNK) domain of UDP-N-acetylglucosamine-2-epimerase/N-acetylmannosamine kinase in complexes with ManNAc at 1.64 Å resolution, MNK·ManNAc·ADP (1.82 Å) and MNK·ManNAc 6-phosphate · ADP (2.10 Å). Our findings offer detailed insights in the active center of MNK and serve as a structural basis to design inhibitors. We synthesized a novel inhibitor, 6-O-acetyl-ManNAc, which is more potent than those previously tested. Specific inhibitors of sialic acid biosynthesis may serve to further study biological functions of sialic acid.
authors.affiliation: From the Institut für Chemie und Biochemie-Kristallographie, Freie Universität Berlin, Takustrasse 6, 14195 Berlin.
authors.forename: Jacobo
authors.initials: J
authors.lastname: Martinez
authors.forename: Long Duc
authors.initials: LD
authors.lastname: Nguyen
authors.forename: Stephan
authors.initials: S
authors.lastname: Hinderlich
authors.forename: Reinhold
authors.initials: R
authors.lastname: Zimmer
authors.forename: Eva
authors.initials: E
authors.lastname: Tauberger
authors.forename: Werner
authors.initials: W
authors.lastname: Reutter
authors.forename: Wolfram
authors.initials: W
authors.lastname: Saenger
authors.forename: Hua
authors.initials: H
authors.lastname: Fan
authors.forename: Sébastien
authors.initials: S
authors.lastname: Moniot
mesh_terms: D001224:Aspartic Acid / Q000737:chemistry; D001665:Binding Sites; D002462:Cell Membrane / Q000378:metabolism; D018360:Crystallography, X-Ray / Q000379:methods; D019281:Dimerization; D004791:Enzyme Inhibitors / Q000737:chemistry; D004926:Escherichia coli / Q000378:metabolism; D006001:Glycoconjugates / Q000737:chemistry; D006023:Glycoproteins / Q000737:chemistry; D006595:Hexosamines / Q000737:chemistry*; D006801:Humans; D019158:N-Acetylneuraminic Acid / Q000737:chemistry; D010766:Phosphorylation; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000037:antagonists & inhibitors / Q000737:chemistry*; D017510:Protein Folding; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000737:chemistry; D015032:Zinc / Q000737:chemistry
chemical_list: D004791:Enzyme Inhibitors; D006001:Glycoconjugates; D006023:Glycoproteins; D006595:Hexosamines; D011994:Recombinant Proteins; D001224:Aspartic Acid; D017853:Phosphotransferases (Alcohol Group Acceptor); C018765:N-acylmannosamine kinase; D019158:N-Acetylneuraminic Acid; D015032:Zinc; C002022:N-acetylmannosamine