The biosynthesis of the extracellular polysaccharide xanthan in Xanthomonas campestris pv. campestris is directed by a cluster of 12 genes, gumB-gumM. Several xanthan-deficient mutants of the wild-type strain 8004 have previously been described which carry Tn5 insertions in this region of the chromosome. Here it is shown that the transposon insertion in one of these mutants, strain 8397, is located 15 bp upstream of the translational start site of the gumB gene. EDTA-treated cells of strain 8397 were able to synthesize the lipid-linked pentasaccharide repeating unit of xanthan from the three nucleotide sugar donors (UDP-glucose, GDP-mannose and UDP-glucuronic acid) but were unable to polymerize the pentasaccharide into mature xanthan. A subclone of the gum gene cluster carrying gumB and gumC restored xanthan production to strain 8397 to levels approximately 28% of the wild-type. In contrast, subclones carrying gumB or gumC alone were not effective. These results are discussed with reference to previous speculations, based on computer analysis, that gumB and gumC are both involved in the translocation of xanthan across the bacterial membranes.
Barrfere,G. C., Barber,C. E., Daniels,M. J.(1986); Molecular cloning of genes involved in the production of the extracellular polysaccharide xanthan by Xanthomonas campestris pv. campestris.. International Journal of Biological Macromolecules, 8,:372–374
Bray,G. A.(1960); A simple efficient liquid scintillator for counting aqueous solutions in a liquid scintillation counter.. Analytical Biochemistry, 1,:279–285
Cadmus,M. C., Rojovin,S. P., Burton,K. A., Pittsley,J. E., Knutson,C. A. et al.(1976); Colonial variation in Xanthomonas campestris NRRL B-1459 and characterization of the polysaccharide of a variant strain.. Canadian Journal of Microbiology, 22,:942–948
Capage,M. A., Doherty,D. H., Betlach,M. R., Vanderslice,R. W.(1987); Recombinant-DNA mediated production of xanthan gum.. International patent WO87/05938.
Couso,R. O., lelpi,L., Garcia,R. C., Dankert,M. A.(1982); Biosynthesis of polysaccharides in Acetobacter xylinum. Sequential synthesis of a heptasaccharide diphosphate prenol.. European Journal of Biochemistry, 123,:617–627
Ditta,G., Schmidhauser,T., Yakobson,E., Lu,P., Liang,X.-W. et al.(1985); Plasmid related to the broad host range vector pRK290, useful for gene cloning and monitoring gene expression.. Plasmid, 13,:149–153
Garcia,R. C., Recondo,E., Dankert,M. A.(1974); Polysaccharide biosynthesis in Acetobacter xylinum. Enzymatic synthesis of lipid diphosphate and monophosphate sugars.. European Journal of Biochemistry, 43,:93–105
Glucksmann,M. A., Reuber,T. L., Walker,G. C.(1993a); Family of glycosyl transferases needed for the synthesis of succinoglycan by Rhizobium meliloti.. Journal of Bacteriology, 175,:7033–7044
Glucksmann,M. A., Reuber,T. L., Walker,G. C.(1993b); Genes needed for the modification, polymerization, export, and processing of succinoglycan by Rhizobium meliloti: a model for succinoglycan biosynthesis.. Journal of Bacteriology, 175,:7045–7055
Harding,N. E., Cleary,J. M., Cabanas,D. K., Rosen,I. G., Kang,K. S.(1987); Genetic and physical analysis of genes essential for xanthan gum biosynthesis in Xanthomonas campestris.. Journal of Bacteriology, 169,:2854–2861
Hull,R. A., Gill,R. E., Hsu,P., Minshew,B. H., Falcow,S.(1981); Construction and expression of recombinant plasmids encoding type 1 or D-mannose-resistant pili from a urinary tract infection Escherichia coli isolate.. Infection and Immunity, 33,:933–938
lelpi,L., Couso,R. O.,
DankertM. A.(1981b); Pyruvic acid acetal residues are transferred from phosphoenolpyruvate to the pentasaccharide-P-P-lipid.. Biochem Biophys Res Commun, 102,:1400–1408
lelpi,L., Couso,R. O., Dankert,M. A.(1993); Sequential assembly and polymerization of the prenol-linked pentasaccharide repeating unit of the xanthan polysaccharide in Xanthomonas campestris.. Journal of Bacteriology, 175,:2490–2500
Marzocca,M. P., Harding,N. E, PetroniE. A.,, Cleary,J. M.,
lelpiL.
(1991); Location and cloning of the ketal pyruvate transferase gene of Xanthomonas campestris,. 1 Bacteriol 173:7519–7524
MUller,P., Weng,M. W. M., Quandt,J., Arnold,W.,
PühlerA.
(1993); Genetic analysis of Rhizobium meliloti exoYFQ operon: ExoY is homologous to sugar transferases and ExoQ represents a transmembrane protein.. Mol Plant-Microbe Int, 6,:55–65
Paulsen,I. T., Beness,A. M.,
SaierM. H.,Jr.
(1997); Computer- based analyses of the protein constituents of transport systems catalysing export of complex carbohydrates in bacteria.. Microbiology, 143,:2685–2699
Pollock,T. J., Thorne,L., Yamazaki,M., Mikolajczak,M.,
ArmentroutR. W.
(1994); Mechanisms of bacitracin resistance in Gram-negative bacteria that synthesise exopolysaccharides.. Journal of Bacteriology, 176,:6229–6237
Stankowski,J. D., Mueller,B. E.,
ZellerS. G.
(1993); Location of a second O-acetyl group in xanthan gum by the reductive- cleavage method.. Carbohydr Res, 241,:321–326
Thorne,L., Tansey,L.,
PollockT. J.
(1987); Clustering of mutations blocking synthesis of xanthan gum by Xanthomonas campestris.. ] Bacteriol, 169,:3593–3600
Turner,P., Barber,C.,
DanielsM. J.
(1984); Behavior of the transposons Tn5 and Tn7 in Xanthomonas campestris pv. campestris.. Molecular & General Genetics, 195,:101–107
Turner,P., Barber,C.,
DanielsM. J.
(1985); Evidence for clustered pathogenicity genes in Xanthomonas campestris pv. campestris.. Molecular & General Genetics, 199,:338–343
Vanderslice,R. W., Doherty,D. H., Capage,M. A., Betlach,M. R., Hassler,R. A. et al.(1990) Genetic engineering of polysaccharide structure in Xanthomonas campestris.. Edited by
CrescenziV.,
DeaI. C. M.,
PaolettiS.,
StivalaS. S.,
SutherlandC. I. W.Biomedical and Biotechnological Advances in Industrial Polysaccharides. New York:: Gordon &C Breach,;145–156