Identification of a gene cluster for the formation of extracellular polysaccharide precursors in the chemolithoautotroph Acidithiobacillus ferrooxidans
No Thumbnail Available
Date
2005-06-01
Authors
Profesor/a GuÃa
Facultad/escuela
Idioma
en
Journal Title
Journal ISSN
Volume Title
Publisher
AMER SOC MICROBIOLOGY
Nombre de Curso
item.page.dc.rights
CC BY 4.0
ATRIBUCIÓN 4.0 INTERNACIONAL
Deed
item.page.dc.rights
https://creativecommons.org/licenses/by/4.0/deed.es
Abstract
A cluster of five genes, proposed to be involved in the formation of extracellular polysaccharide (EPS) precursors via the Leloir pathway, have been identified in the acidophilic autotroph Acidithiobacillus ferrooxidans. The order of the genes is luxA-galE-galK-pgm-galM, encoding a LuxA-like protein, UDP-glucose 4-epimerase, galactokinase, phosphoglucomutase, and galactose mutarotase, respectively. The gal cluster forms a single transcriptional unit and is therefore an operon. Two other putative genes of the Leloir pathway, galU, potentially encoding UDP-glucose pyrophosphorylase, and a gene designated galT-like, which may encode a gallactose-1-phosphate uridylyltransferase-like activity, were found unlinked in the genome. Using semiquantitative reverse transcription-PCR, the genes of the gal operon were shown to be expressed more during growth in iron medium than in growth in sulfur medium. The functions of galE, pgm, galU, and the galT-like gene were validated by complementation of Escherichia coli mutants and by in vitro enzyme assays. The data suggest that A. ferrooxidans is capable of synthesizing the EPS precursors UDP-glucose and UDP-galactose. In addition, genes rfbA, -B, -C, and -D were identified in the genome of A. ferrooxidans, suggesting that it can also synthesize the EPS precursor dTDP-rhamnose. Since EPSs constitute the major bulk of biofilms, this study may provide an initial model for the metabolic pathways involved in biofilm formation in A. ferrooxidans and aid in understanding the role of biofilms in mineral leaching and the formation of acid mine drainage.
item.page.dc.description
INDEXACIÓN: WEB OF SCIENCE.
Keywords
COLI GALACTOSE OPERON, THIOBACILLUS-FERROOXIDANS, ESCHERICHIA-COLI, EXOPOLYSACCHARIDE PRODUCTION, STREPTOCOCCUS-THERMOPHILUS, F-420-DEPENDENT GLUCOSE-6-PHOSPHATE-DEHYDROGENASE, BIOSYNTHESIS, PYROPHOSPHORYLASE, MYCOBACTERIUM, EXPRESSION
Citation
APPLIED AND ENVIRONMENTAL MICROBIOLOGY, Volume 71, Issue 6, Page 2902-2909
DOI
10.1128/AEM.71.6.2902-2909.2005