1s67
From Proteopedia
Crystal structure of heme domain of direct oxygen sensor from E. coli
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] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe X-ray crystal structure of the Escherichia coli (Ec) direct oxygen sensor heme domain (Ec DosH) has been solved to 1.8 A using Fe multiple-wavelength anomalous dispersion (MAD), and the positions of Met95 have been confirmed by selenomethionine ((Se)Met) MAD. Ec DosH is the sensing part of a larger two-domain sensing/signaling protein, in which the signaling domain has phosphodiesterase activity. The asymmetric unit of the crystal lattice contains a dimer comprised of two differently ligated heme domain monomers. Except for the heme ligands, the monomer heme domains are identical. In one monomer, the heme is ligated by molecular oxygen (O(2)), while in the other monomer, an endogenous Met95 with S --> Fe ligation replaces the exogenous O(2) ligand. In both heme domains, the proximal ligand is His77. Analysis of these structures reveals sizable ligand-dependent conformational changes in the protein chain localized in the FG turn, the G(beta)-strand, and the HI turn. These changes provide insight to the mechanism of signal propagation within the heme domain following initiation due to O(2) dissociation. Insights into signal transduction involving PAS domain oxygen-sensing heme proteins from the X-ray crystal structure of Escherichia coli Dos heme domain (Ec DosH).,Park H, Suquet C, Satterlee JD, Kang C Biochemistry. 2004 Mar 16;43(10):2738-46. PMID:15005609[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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