4hu4 | pdb_00004hu4
Crystal structure of EAL domain of the E. coli DosP - dimeric form
Structural highlights
Function[DOSP_ECOLI] Heme-based oxygen sensor protein displaying phosphodiesterase (PDE) activity toward c-di-GMP in response to oxygen availability. Involved in the modulation of intracellular c-di-GMP levels, in association with DosC which catalyzes the biosynthesis of c-di-GMP (diguanylate cyclase activity). Cyclic-di-GMP is a second messenger which controls cell surface-associated traits in bacteria. Has very poor PDE activity on cAMP (PubMed:15995192) but is not active with cGMP, bis(p-nitrophenyl) phosphate or p-nitrophenyl phosphate (PubMed:11970957). Via its PDE activity on c-di-GMP, DosP regulates biofilm formation through the repression of transcription of the csgBAC operon, which encodes curli structural subunits.[1] Publication Abstract from PubMedThe 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 beta3 and helix alpha3. This element, together with an unordered fragment, replaces the short alpha-helix (named alpha5 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. Structures of the catalytic EAL domain of the Escherichia coli direct oxygen sensor.,Tarnawski M, Barends TR, Hartmann E, Schlichting I Acta Crystallogr D Biol Crystallogr. 2013 Jun;69(Pt 6):1045-53. doi:, 10.1107/S0907444913004423. Epub 2013 May 14. PMID:23695249[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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