Ectoine and hydroxyectoine as protectants against osmotic and cold stress: uptake through the SigB-controlled betaine-choline- carnitine transporter-type carrier EctT from Virgibacillus pantothenticus.

Virgibacillus pantothenticus has been shown to synthesize the compatible solute ectoine in response to high salinity or low growth temperature. We found that exogenously provided ectoine and hydroxyectoine also serve as protectants against these challenges. Transport studies with [(14)C]ectoine revealed that both types of stress induced a high-affinity ectoine uptake activity in V.

Synthesis of 5-hydroxyectoine from ectoine: crystal structure of the non-heme iron(II) and 2-oxoglutarate-dependent dioxygenase EctD.

As a response to high osmolality, many microorganisms synthesize various types of compatible solutes. These organic osmolytes aid in offsetting the detrimental effects of low water activity on cell physiology. One of these compatible solutes is ectoine.

The crystal structure of UehA in complex with ectoine-A comparison with other TRAP-T binding proteins.

Substrate-binding proteins or extracellular solute receptors (ESRs) are components of both ABC (ATP binding cassette) and TRAP-T (tripartite ATP-independent periplasmic transporter). The TRAP-T system UehABC from Silicibacter pomeroyi DSS-3 imports the compatible solutes ectoine and 5-hydroxyectoine as nutrients. UehA, the ESR of the UehABC operon, binds both ectoine and 5-hydroxyectoine with high affinity (K(d) values of 1.

Synthesis and uptake of the compatible solutes ectoine and 5-hydroxyectoine by Streptomyces coelicolor A3(2) in response to salt and heat stresses.

Streptomyces coelicolor A3(2) synthesizes ectoine and 5-hydroxyectoine upon the imposition of either salt (0.5 M NaCl) or heat stress (39 degrees C). The cells produced the highest cellular levels of these compatible solutes when both stress conditions were simultaneously imposed.

Synthesis of the compatible solute ectoine in Virgibacillus pantothenticus is triggered by high salinity and low growth temperature.

The quantification of the intracellular concentration of ectoine in Virgibacillus pantothenticus revealed that the production of this compatible solute is triggered either by an increase in the external salinity or by a reduction in the growth temperature. This finding reflects increased transcription of the ectoine biosynthetic operon (ectABC) under both environmental conditions.

Osmotically induced synthesis of the compatible solute hydroxyectoine is mediated by an evolutionarily conserved ectoine hydroxylase.

By using natural abundance (13)C NMR spectroscopy, we investigated the types of compatible solutes synthesized in a variety of Bacilli under high salinity growth conditions. Glutamate, proline, and ectoine were the dominant compatible solutes synthesized by the various Bacillus species. The majority of the inspected Bacilli produced the tetrahydropyrimidine ectoine in response to high salinity stress, and a subset of these also synthesized a hydroxylation derivative of ectoine, 5-hydroxyectoine.

Purification and characterization of the methylene tetrahydromethanopterin dehydrogenase MtdB and the methylene tetrahydrofolate dehydrogenase FolD from Hyphomicrobium zavarzinii ZV580.

Recently, it has been shown that heterotrophic methylotrophic Proteobacteria contain tetrahydrofolate (H(4)F)- and tetrahydromethanopterin (H(4)MPT)-dependent enzymes. Here we report on the purification of two methylene tetrahydropterin dehydrogenases from the methylotroph Hyphomicrobium zavarzinii ZV580. Both dehydrogenases are composed of one type of subunit of 31 kDa.