Structural Characterisation of the Core Oligosaccharides Isolated from the Lipooligosaccharide Fraction of Agrobacterium tumefaciens A1

Abstract

Three different oligosaccharide structures from the lipooligosaccharide fraction of Agrobacterium tumefaciens strain A1 were determined by means of chemical and spectrometrical methods. The peculiar feature of this oligosaccharide family consisted of its unusual length, that was very close to the that minimal requested for the external membrane functionality as exemplified from oligosaccharide 3, where the inner core is glycosylated from only one sugar moiety onwards.

Synthesis of a Pentasaccharide Fragment Related to the Inner Core Region of Rhizobial and Agrobacterial Lipopolysaccharides

“… 6 Specifically, 5- O -mannosylated Kdo has been found in bacteria such as Francisella tularensis , Brucella melitensis , Agrobacterium tumefaciens , Sinorhizobium meliloti and Rhizobiaceae . 2 , 7 In the latter strains, defects in the mannosyl transferase LpsC impairs their nodulation activity. 8 , 9 Recently, the structure of an oligomannose linked to O-5 of Kdo was reported for the inner core of the lipooligosaccharide (LOS) of Rhizobium radiobacter Rv3, also termed Agrobacterium radiobacter and Agrobacterium tumefaciens ( Figure 1 ).…”

“…In many bacterial genera, this Kdo unit is then extended by a lateral α-(2 → 4)-linked Kdo moiety and further elongated at position 5 by additional inner core sugars such as l - glycero - d - manno -heptose ( l , d -Hep), d -glucose, d -galacturonic acid or d -mannose . Specifically, 5- O -mannosylated Kdo has been found in bacteria such as Francisella tularensis , Brucella melitensis , Agrobacterium tumefaciens , Sinorhizobium meliloti and Rhizobiaceae . , In the latter strains, defects in the mannosyl transferase LpsC impairs their nodulation activity. , Recently, the structure of an oligomannose linked to O-5 of Kdo was reported for the inner core of the lipooligosaccharide (LOS) of Rhizobium radiobacter Rv3, also termed Agrobacterium radiobacter and Agrobacterium tumefaciens (Figure ). , Of note is the structural resemblance of the α-(1 → 2)-linked oligomannose part to the D1 arm of mammalian high-mannose glycans, which are particularly abundant on HIV-1 gp120 …”