A Second Outer-Core Region in Klebsiella pneumoniae Lipopolysaccharide

Abstract

Up to now only one major type of core oligosaccharide has been found in the lipopolysaccharide of all Klebsiella pneumoniae strains analyzed. Applying a different screening approach, we identified a novel Klebsiella pneumoniae core (type 2). Both Klebsiella core types share the same inner core and the outer-core-proximal disaccharide, GlcN-(1,4)-GalA, but they differ in the GlcN substituents. In core type 2, the GlcpN residue is substituted at the O-4 position by the disaccharide ␤-Glcp(1-6)-␣-Glcp(1, while in core type 1 the GlcpN residue is substituted at the O-6 position by either the disaccharide ␣-Hep(1-4)-␣-Kdo(2 or a Kdo residue (Kdo is 3-deoxy-D-manno-octulosonic acid). This difference correlates with the presence of a three-gene region in the corresponding core biosynthetic clusters. Engineering of both core types by interchanging this specific region allowed studying the effect on virulence. The replacement of Klebsiella core type 1 in a highly type 2 virulent strain (52145) induces lower virulence than core type 2 in a murine infection model.

Three Enzymatic Steps Required for the Galactosamine Incorporation into Core Lipopolysaccharide

“…4B). These structures are in agreement with a full type 2 K. pneumoniae core OS (13). Other signals attributable to OS with terminal Kdo modifications or sodium abducts are shown in Fig.…”

“…P. mirabilis core OS structures and genetic organization of the core OS biosynthetic clusters. A, the common part of core OS shared by all of the studied strains of P. mirabilis (11), K. pneumoniae, and S. marcescens (11,13,14). Broken lines denote the truncation level for the different core biosynthetic gene mutations (13,14,15,16,35).…”

“…11). This common fragment is also found in the core LPS of Klebsiella pneumoniae and Serratia marcescens (12)(13)(14), and we have shown that two enzymes are required for the incorporation of GlcN into the core LPS of K. pneumoniae: the WabH enzyme catalyzing the incorporation of GlcNAc from UDP-GlcNAc to outer core LPS and WabN catalyzing the deacetylation of the incorporated GlcNAc (15). The rest of the Proteus core OS is quite variable, with up to 37 different structures recognized in the genus Proteus and 11 in P. mirabilis (11).…”

The Incorporation of Glucosamine into Enterobacterial Core Lipopolysaccharide

“…1). Furthermore the functions in both inner and outer core biosynthesis of most of the transferases encoded by the wa gene products have been elucidated (7)(8)(9)(10)(11)(12) (Fig. 1).…”

“…The genes involved in the K. pneumoniae core LPS biosynthesis are clustered in a region (wa) of the K. pneumoniae chromosome, and two different clusters have been identified to be responsible for type 1 and type 2 core biosynthesis (7,8) (Fig. 1).…”