Open AccessConstruction and characterization of an NaCl‐sensitive mutant of Halomonas elongata impaired in ectoine biosynthesis
Author(s) -
Göller Karin,
Ofer Alexandra,
Galinski Erwin A
Publication year - 1998
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1998.tb12960.x
Subject(s) - ectoine , halomonas , biology , biosynthesis , biochemistry , mutant , halophile , microbiology and biotechnology , gene , genetics , amino acid , osmoprotectant , bacteria , proline
Using transposon mutagenesis we generated a salt‐sensitive mutant of the halophilic eubacterium Halomonas elongata impaired in the biosynthesis of the compatible solute ectoine. HPLC determinations of the cytoplasmic solute content showed the accumulation of a biosynthetic precursor of ectoine, l ‐2,4‐diaminobutyric acid. Ectoine and hydroxyectoine were not detectable. This mutant failed to grow in minimal medium with NaCl concentrations exceeding 4%. However, when supplemented with organic osmolytes, the ability to grow in high‐salinity medium (15% and higher) was regained. We cloned and sequenced the regions flanking the transposon insertion in the H. elongata chromosome. Sequence comparisons with known proteins revealed significant similarity of the mutated gene to the l ‐2,4‐diaminobutyric acid acetyltransferase from the ectoine biosynthetic pathway in Marinococcus halophilus . Analysis of a PCR product demonstrated that the ectoine biosynthetic genes ( ectABC ) follow the same order as in M. halophilus .