Expression of a cloned cyclopropane fatty acid synthase gene reduces solvent formation in Clostridium acetobutylicum ATCC 824.
The cyclopropane fatty acid synthase gene (cfa) of Clostridium acetobutylicum ATCC 824 was cloned and overexpressed under the control of the clostridial ptb promoter. The function of the cfa gene was confirmed by complementation of an Escherichia coli cfa-deficient strain in terms of fatty acid composition and growth rate under solvent stress. Constructs expressing cfa were introduced into C. acetobutylicum hosts and cultured in rich glucose broth in static flasks without pH control. Overexpression of the cfa gene in the wild type and in a butyrate kinase-deficient strain increased the cyclopropane fatty acid content of early-log-phase cells as well as initial acid and butanol resistance. However, solvent production in the cfa-overexpressing strain was considerably decreased, while acetate and butyrate levels remained high. The findings suggest that overexpression of cfa results in changes in membrane properties that dampen the full induction of solventogenesis. The overexpression of a marR homologous gene preceding the cfa gene in the clostridial genome resulted in reduced cyclopropane fatty acid accumulation.
Department of Biochemistry and Cell Biology, Rice University, Houston, TX 77005, USA.
Yinsuo
Y
Zhao
Lucia A
LA
Hindorff
Amy
A
Chuang
Melanie
M
Monroe-Augustus
Michael
M
Lyristis
Mary L
ML
Harrison
Frederick B
FB
Rudolph
George N
GN
Bennett
D000433:1-Propanol / Q000378:metabolism; D001426:Bacterial Proteins / Q000378:metabolism; D000440:Butanols / Q000378:metabolism; D020148:Butyric Acid / Q000378:metabolism; D003001:Cloning, Molecular; D003013:Clostridium / Q000201:enzymology* / Q000235:genetics*; D003521:Cyclopropanes / Q000737:chemistry; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics; D000431:Ethanol / Q000378:metabolism; D005227:Fatty Acids / Q000096:biosynthesis / Q000737:chemistry; D015870:Gene Expression; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D007700:Kinetics; D008780:Methyltransferases / Q000235:genetics* / Q000378:metabolism*; D010766:Phosphorylation; D017851:Phosphotransferases (Carboxyl Group Acceptor) / Q000235:genetics / Q000378:metabolism; D010957:Plasmids / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics; D012997:Solvents / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism
D001426:Bacterial Proteins; D000440:Butanols; D003521:Cyclopropanes; D029968:Escherichia coli Proteins; D005227:Fatty Acids; C080004:MarR protein, E coli; D012097:Repressor Proteins; D012997:Solvents; C080950:Spo0A protein, Bacillus subtilis; D014157:Transcription Factors; C028775:cyclopropane fatty acids; D020148:Butyric Acid; D000431:Ethanol; D000433:1-Propanol; D008780:Methyltransferases; C019964:cyclopropane synthetase; D017851:Phosphotransferases (Carboxyl Group Acceptor); C019285:butyrate kinase