PROSITE documentation PDOC50883
EAL domain profile


The EAL domain is an around 250-amino acid signaling domain. It is made of four conserved regions and has been named EAL according to a conserved sequence within the second of these regions. The EAL domain is found in a large number of eubacterial multi-domain proteins involved in signal transduction. The EAL domain is found in association with other domains of the prokaryotic two-component signal transduction systems, such as the GGDEF domain (see <PDOC50887>), the response regulatory domain (see <PDOC50110>), the PAS repeat and the PAC domain (see <PDOC50112>), the MHYT domain, the HAMP domain (see <PDOC50885>), the GAF domain, the TPR repeat, or the FHA domain (see <PDOC50006>). It has been proposed that the EAL domain might function as a diguanylate phosphodiesterase. Accordingly, it contains several conserved acidic residues that could participate in metal binding and potentially might form a phosphodiesterase active site [1,2,3].

Some proteins known to contain an EAL domain are listed below:

  • Acetobacter xylinum diguanylate cyclase (DGC).
  • Acetobacter xylinum phosphodiesterase A (gene pdeA).
  • Bacillus subtilis hypothetical protein ykoW.
  • Bordetella pertussis bvgR protein.
  • Escherichia coli rtn protein. It is involved in resistance to phages N4 and lambda.
  • Escherichia coli hypothetical protein yahA.
  • Escherichia coli hypothetical protein yciR.
  • Escherichia coli hypothetical protein yddU.
  • Escherichia coli hypothetical protein yfeA.
  • Escherichia coli protein yhjK.
  • Escherichia coli hypothetical protein yjcC.
  • Klebsiella pneumoniae fimK protein.
  • Mycobacterium tuberculosis hypothetical protein Rv1354c.
  • Rhizobium sp. strain NGR234 hypothetical protein Y4LL.
  • Synechocystis sp. strain PCC 6803 nitrogen fixation positive activator protein.
  • Synechocystis sp. strain PCC 6803 hypothetical protein slr0359.

The profile we developed covers the entire EAL domain.

Last update:

December 2002 / First entry.


Technical section

PROSITE method (with tools and information) covered by this documentation:

EAL, PS50883; EAL domain profile  (MATRIX)


1AuthorsTal R. Wong H.C. Calhoon R. Gelfand D. Fear A.L. Volman G. Mayer R. Ross P. Amikam D. Weinhouse H. Cohen A. Sapir S. Ohana P. Benziman M.
TitleThree cdg operons control cellular turnover of cyclic di-GMP in Acetobacter xylinum: genetic organization and occurrence of conserved domains in isoenzymes.
SourceJ. Bacteriol. 180:4416-4425(1998).
PubMed ID9721278

2AuthorsMerkel T.J. Barros C. Stibitz S.
TitleCharacterization of the bvgR locus of Bordetella pertussis.
SourceJ. Bacteriol. 180:1682-1690(1998).
PubMed ID9537363

3AuthorsGalperin M.Y. Nikolskaya A.N. Koonin E.V.
TitleNovel domains of the prokaryotic two-component signal transduction systems.
SourceFEMS Microbiol. Lett. 203:11-21(2001).
PubMed ID11557134

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