Role of betaine:CoA ligase (CaiC) in the activation of betaines and the transfer of coenzyme A in Escherichia coli.
OBJECTIVE
Characterization of the role of CaiC in the biotransformation of trimethylammonium compounds into l(-)-carnitine in Escherichia coli.


RESULTS
The caiC gene was cloned and overexpressed in E. coli and its effect on the production of l(-)-carnitine was analysed. Betaine:CoA ligase and CoA transferase activities were analysed in cell free extracts and products were studied by electrospray mass spectrometry (ESI-MS). Substrate specificity of the caiC gene product was high, reflecting the high specialization of the carnitine pathway. Although CoA-transferase activity was also detected in vitro, the main in vivo role of CaiC was found to be the synthesis of betainyl-CoAs. Overexpression of CaiC allowed the biotransformation of crotonobetaine to l(-)-carnitine to be enhanced nearly 20-fold, the yield reaching up to 30% (with growing cells). Higher yields were obtained using resting cells (up to 60%), even when d(+)-carnitine was used as substrate.


CONCLUSIONS
The expression of CaiC is a control step in the biotransformation of trimethylammonium compounds in E. coli.


CONCLUSIONS
A bacterial betaine:CoA ligase has been characterized for the first time, underlining its important role for the production of l-carnitine with Escherichia coli.
Bernal
V
V
Departamento de Bioquímica y Biología Molecular B e Inmunología, Facultad de Química, Universidad de Murcia, Murcia, Spain.
Arense
P
P
Blatz
V
V
Mandrand-Berthelot
M A
MA
Cánovas
M
M
Iborra
J L
JL
D001622:Betaine / Q000378:metabolism*; D019149:Bioreactors; D002331:Carnitine / Q000096:biosynthesis; D002851:Chromatography, High Pressure Liquid; D003001:Cloning, Molecular; D003065:Coenzyme A / Q000378:metabolism*; D003066:Coenzyme A Ligases / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D029968:Escherichia coli Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D005798:Genes, Bacterial; D005822:Genetic Vectors; D007218:Industrial Microbiology; D007220:Industrial Waste; D016133:Polymerase Chain Reaction / Q000379:methods; D021241:Spectrometry, Mass, Electrospray Ionization; D013379:Substrate Specificity; D050337:Trimethyl Ammonium Compounds / Q000378:metabolism
D029968:Escherichia coli Proteins; D007220:Industrial Waste; D050337:Trimethyl Ammonium Compounds; D001622:Betaine; D003066:Coenzyme A Ligases; C091402:caiC protein, E coli; D002331:Carnitine; D003065:Coenzyme A