Cloning and characterization of the genes for biosynthesis of the compatible solute ectoine in the moderately halophilic bacterium Halobacillus dabanensis D-8(T).

A 11.2-kb fragment containing the ectABC genes of the biosynthetic pathway of ectoine from the Gram-positive, moderately halophilic bacterium Halobacillus dabanensis D-8(T) was obtained by inverse polymerase chain reaction. Subsequently, the entire ectABC cluster was cloned and analyzed. It revealed that the intergenic regions of the ectABC genes from H. dabanensis D-8(T) are more tightly spaced than those of Chromohalobacter salexigens, Halomonas elongata, Marinococcus halophilus, and Salibacillus pasteurii. The amino-acid sequence deduced from ectABC was highly homologous that from Virgibacillus pantethenticus (EctA 52%, EctB 60%, EctC 67%, respectively). The ectABC genes were cloned in the expression plasmid pMXB10 resulting in pMXB10ectABC. The ectoine was detected from cell extract in Escherishia coli ER2566 containing pMXB10ectABC using (13)C nuclear magnetic resonance spectroscopy.