title: Sialylation of lipopolysaccharide by CMP-NANA in viable gonococci is enhanced by low Mr material released from blood cell extracts but not by some UDP sugars.
abstract: Serum resistance of gonococci in most patients is due to sialylation of a Gal beta 1-4GlcNAc group on a conserved 4.5 kDa lipopolysaccharide (LPS) component by host cytidine 5'-monophospho-N-acetyl neuraminic acid (CMP-NANA) catalysed by a gonococcal sialyl transferase. This sialylation is enhanced by a low M(r) factor(s) which, like CMP-NANA, is released in diffusates from high M(r) fractions obtained from sonicates dialysed at 4 degrees C. Also, as shown here, this factor(s) is released when the sonicates are dialysed at 18-20 degrees C. The enhancement of sialylation, first demonstrated using enzymes in gonococcal extracts, has been shown to occur in live gonococci and hence probably to have a role in pathogenicity. Gonococci, emerging from lag phase and incubated for 2 h with CMP-14CNANA fixed up to 90% more radiolabel than controls when the second factor(s) was present; their LPS separated by SDS-PAGE contained more radiolabel than control samples and label was not detected in any other component. Fractions with enhancing activity absorbed maximally at about 260 nm but a mixture of UDP-galactose (UDP-Gal), UDP-N-Acetyl galactosamine (UDP-GalNAc), UDP-glucose (UDP-Glc) and UDP-N-Acetyl glucosamine (UDP-GlcNAc) showed no significant enhancing activity. The enhancing action of the low M(r) fractions was unaffected by incubation with beta-galactosidase.
authors: School of Biochemistry, University of Birmingham, U.K.
authors: N J
authors: NJ
authors: Parsons
authors: C
authors: C
authors: Constantinidou
authors: J A
authors: JA
authors: Cole
authors: H
authors: H
authors: Smith
mesh_terms: D001770:Blood Bactericidal Activity; D002240:Carbohydrate Sequence; D003569:Cytidine Monophosphate N-Acetylneuraminic Acid / Q000378:metabolism*; D006069:Gonorrhea / Q000097:blood / Q000382:microbiology; D006801:Humans; D066298:In Vitro Techniques; D008070:Lipopolysaccharides / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D008969:Molecular Sequence Data; D009344:Neisseria gonorrhoeae / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D012794:Sialic Acids / Q000737:chemistry / Q000378:metabolism; D014539:Uridine Diphosphate Sugars / Q000494:pharmacology
chemical_list: D008070:Lipopolysaccharides; D012794:Sialic Acids; D014539:Uridine Diphosphate Sugars; D003569:Cytidine Monophosphate N-Acetylneuraminic Acid