Glycosyltransferases for biosynthesis of oligosaccharides, and genes encoding them

Abstract

The present invention is directed to nucleic acids encoding glycosyltransferases, the proteins encoded thereby, and to methods for synthesizing oligosaccharides using the glycosyltransfereses of the invention. In particular, the present application is directed to identification a glycosyltransferase locus of Neisseria gonorrhoeae containing five open reading frames for five different glycosyltransferases. The functionally active glycosyltransferases of the invention are characterized by catalyzing reactions such as adding Gal β1→4 to GlcNAc or Glc; adding GalNAc or GlcNAc β1→3 to Gal; and adding Gal α1→4 to Gal. The glycosyltransferases of the invention are particularly suited to the synthesis of the oligosaccharides Galβ1→4GlcNAcβ1→3Galβ1→4Glc (a mimic of lacto-N-neotetraose), GalNAcβ1→3Galβ1→4GlcNAcβ1→3Galβ1→4Glcβ1→4 (a mimic a ganglioside), and Galα1→4Galβ1→4Glcβ1→4Hep→R (a mimic of the saccharide portion of globo-glycolipids).

1 . A  Neisserial  strain having an open reading frame encoding a glycosyltransferase, selected from the list consisting of: LgtA, LgtB, LgtC, LgtD, and LgtE, which has been deleted such that it no longer expresses said glycosyltransferase.  
     
     
         2 . A vaccine preparation effective against  Neisserial  strains, said preparation comprising an altered  Neisserial  oligosaccharide structure prepared from the  Neisserial  strain of  claim 1 .  
     
     
         3 . A process of making an altered  Neisserial  oligosaccharide structure comprising the steps of deleting an open reading frame encoding a glycosyltransferase from a  Neisserial  strain selected from the list consisting of: LgtA, LgtB, LgtC, LgtD, and LgtE, and preparing the altered  Neisserial  oligosaccharide structure from said strain.  
     
     
         4 . A process of making a vaccine preparation effective against  Neisserial  strains, comprising the steps of deleting an open reading frame encoding a glycosyltransferase from a  Neisserial  strain selected from the list consisting of: LgtA, LgtB, LgtC, LgtD, and LgtE, preparing an altered  Neisserial  oligosaccharide structure from said strain, and formulating said altered  Neisserial  oligosaccharide structure in a vaccine preparation.