Evidence for a role for the gumB and gumC gene products in the formation of xanthan from its pentasaccharide repeating unit by Xanthomonas campestris.
Microbiology (Reading)
; 144 ( Pt 6): 1487-1493, 1998 Jun.
Article
em En
| MEDLINE
| ID: mdl-9639919
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.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Polissacarídeos Bacterianos
/
Proteínas de Bactérias
/
Xanthomonas campestris
/
Genes Bacterianos
Idioma:
En
Revista:
Microbiology (Reading)
Assunto da revista:
MICROBIOLOGIA
Ano de publicação:
1998
Tipo de documento:
Article
País de afiliação:
Argentina
País de publicação:
Reino Unido