Characterization of the ectoine biosynthesis genes of haloalkalotolerant obligate methanotroph "Methylomicrobium alcaliphilum 20Z"

Arch Microbiol. 2006 Jan;184(5):286-97. doi: 10.1007/s00203-005-0042-z. Epub 2005 Nov 10.


The genes involved in biosynthesis of the major compatible solute ectoine (1,4,5,6-tetrahydro-2-methylpyrimidine carboxylic acid) in halotolerant obligate methanotroph "Methylomicrobium alcaliphilum 20Z" were studied. The complete nucleotide sequences of the structural genes encoding L: -aspartokinase (Ask), L-2,4-diaminobutyric acid transaminase (EctB), L-2,4-diaminobutyric acid acetyltransferase (EctA), and L-ectoine synthase (EctC) were defined and shown to be transcribed as a single operon ectABCask. Phylogenetic analysis revealed high sequence identities (34-63%) of the Ect proteins to those from halophilic heterotrophs with the highest amino acid identities being to Vibrio cholerae enzymes. The chromosomal DNA fragment from "M. alcaliphilum 20Z" containing ectABC genes and putative promoter region was expressed in Escherichia coli. Recombinant cells could grow in the presence of 4% NaCl and synthesize ectoine. The data obtained suggested that despite the ectoine biosynthesis pathway being evolutionary well conserved with respect to the genes and enzymes involved, some differences in their organization and regulation could occur in various halophilic bacteria.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Amino Acids, Diamino / biosynthesis*
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / genetics*
  • Bacterial Proteins / metabolism
  • Base Sequence
  • Cloning, Molecular
  • Gene Expression Regulation, Bacterial*
  • Genes, Bacterial*
  • Hydro-Lyases / genetics
  • Hydro-Lyases / metabolism
  • Hydrogen-Ion Concentration
  • Methylococcaceae / enzymology*
  • Methylococcaceae / genetics
  • Methylococcaceae / growth & development
  • Molecular Sequence Data
  • Multigene Family
  • Sequence Analysis, DNA
  • Sodium Chloride


  • Amino Acids, Diamino
  • Bacterial Proteins
  • Sodium Chloride
  • ectoine
  • Hydro-Lyases
  • ectoine synthase

Associated data

  • GENBANK/DQ016501