Hydroxyectoine overproduction by the natural producer Chromohalobacter salexigens is presented in this study. Genetically engineered strains were constructed that at low salinity coexpressed, in a vector derived from a native plasmid, the ectoine (ectABC) and hydroxyectoine (ectD) genes under the control of the ectA promoter, in a temperature-independent manner. Hydroxyectoine production was fu...

OBJECTIVE To study crystallization and X-Ray diffraction of ectoine hydroxylase from Bacillus pseudofirmus OF4. METHODS We cloned the gene BpectD from B. pseudofirmus OF4 with a His6 tag and overexpressed it in E. coli BL21 (DE3). Then, we purified protein BpEctD by Ni2 -chelating affinity and size-exclusion chromatography. After that, crystals were grown by the sitting-drop vapour-diffusion ...

Genes encoding key enzymes of the ectoine biosynthesis pathway in the halotolerant obligate methanotroph Methylomicrobium alcaliphilum 20Z have been shown to be organized into an ectABC-ask operon. Transcription of the ect operon is initiated from two promoters, ectAp(1) and ectAp(2) (ectAp(1)p(2)), similar to the sigma(70)-dependent promoters of Escherichia coli. Upstream of the gene cluster, ...

The osmoregulatory pathways of the moderately halophilic bacterium Halomonas elongata DSM 3043 have been investigated. This strain grew optimally at 1.5 to 2 M NaCl in M63 glucose-defined medium. It required at least 0.5 M NaCl for growth, which is a higher concentration than that exhibited by the H. elongata type strain ATCC 33173. Externally provided betaine, choline, or choline-O-sulfate (bu...

Drought and salinity are among the worst scourges of agriculture. One effective mechanism to reduce damage from these stresses is the accumulation of high intracellular levels of osmoprotectant compounds. These compounds include proline, ectoine, betaines, polyols, and trehalose and have evolved in many different organisms. Since some crop plants have low levels of these osmoprotectants or none...

Compatible solutes like ectoine and its derivatives are deployed by halophile organisms as osmolytes to sustain the high salt concentration in the environment. This work investigates the relation of the thermodynamic properties of compatible solutes and their impact as osmolytes. The ectoines considered in this work are ectoine, hydroxyectoine, and homoectoine. Besides solution densities (15-45...