Abstract
Background and objectives:
important virulence factor for many invasive bacterial pathogens of humans.
Escherichia coli offer a model system to study the mechanisms by which
capsular polysaccharides are synthesized and exported onto the cell surface of
bacteria. Biosynthesis of the E
consists of the repeat structure -4) GlcA- (1, 4)-GlcNAc- (1-, requires the
KfiA, KfiB, KfiC, and KfiD proteins. Until now , the role of all proteins
except KfiB have been kown.
Capsular polysaccharide expression is an. coli K5 capsular polysaccharide, which
Material and Methods
(pMA1) and several derivatives of KfiB expression construct (pMA2-6) were
made with a 6Xhis-tag at the N-terminus. The presence of the hexa histidin tag
facilitated purification of the KfiB protein using Ni
: To study the role of the KfiB protein, a full-length2+-NTA chromatography.
Results:
pPC6::23 and restore capsule production. Successful complementation by
pMA1, showed that the fused hexa-histidine tag did not interrupt the function
of KfiB and that the full-length KfiB is required for complementation.
All plasmids except pMA1 failed to complement the mutation in
Roberts, I.S.
Conclusion:
cytoplasmic membrane.
Localization studies revealed that KfiB is associated with the
Key words:
Escherichia coli, Capsular polysaccharide, KfiB, K5
