Acta Crystallographica Section D

Biological Crystallography

Volume 69, Part 6 (June 2013)


research papers



Acta Cryst. (2013). D69, 1045-1053    [ doi:10.1107/S0907444913004423 ]

Structures of the catalytic EAL domain of the Escherichia coli direct oxygen sensor

M. Tarnawski, T. R. M. Barends, E. Hartmann and I. Schlichting

Abstract: The direct oxygen sensor DosP is a multidomain protein that contains a gas-sensing haem domain and an EAL effector domain. EAL domains are omnipresent signal transduction domains in bacteria. Many EAL domains are active phosphodiesterases and are involved in breakdown of the ubiquitous bacterial second messenger cyclic di-GMP. Despite a great deal of information on the functional and structural aspects of active and inactive EAL domains, little is known about the structural basis of their regulation by their associated sensory domains. Here, two crystal structures of the Escherichia coli DosP EAL domain derived from cubic and monoclinic crystal forms that were obtained under tartrate and PEG conditions, respectively, are described. Both of the structures display the typical TIM (triosephosphate isomerase) barrel fold with one antiparallel [beta]-strand. However, unlike other EAL structures, access to the active site in DosP EAL is sterically restricted by the presence of a short helical stretch (Ser637-Ala-Leu-His640) in loop L3 between strand [beta]3 and helix [alpha]3. This element, together with an unordered fragment, replaces the short [alpha]-helix (named [alpha]5 in Tbd1265 EAL) that is found in other EAL-domain structures. Since DosP EAL is an active c-di-GMP phosphodiesterase, the observed inactive conformation is suggested to be of functional relevance for the regulation mechanism of DosP.

PDB references: 4hu3 and 4hu4

Keywords: EAL domains; phosphodiesterases; cyclic di-GMP; DosP; direct oxygen sensors; Escherichia coli.


pdfdisplay filedownload file

Portable Document Format (PDF) file
[ doi:10.1107/S0907444913004423/cb5026sup1.pdf ]
Supplementary material


Notes:

To open or display or play some files, you may need to set your browser up to use the appropriate software. See the full list of file types for an explanation of the different file types and their related mime types and, where available links to sites from where the appropriate software may be obtained.

The download button will force most browsers to prompt for a file name to store the data on your hard disk.

Where possible, images are represented by thumbnails.

 bibliographic record in  format

  Find reference:   Volume   Page   
  Search:     From   to      Advanced search

Copyright © International Union of Crystallography
IUCr Webmaster