3qqa

Crystal structures of CmeR-bile acid complexes from Campylobacter jejuni

spinqualitylabelsall models 3qqa, resolution 2.20Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3qqa is a 1 chain structure with sequence from Campylobacter jejuni. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: TCH Related: 3qps, 3oqu Gene: cmeR, CmeR (Campylobacter jejuni) Resources: FirstGlance, OCA, RCSB, PDBsum Publication Abstract from PubMed The TetR family of transcription regulators are diverse proteins capable of sensing and responding to various structurally dissimilar antimicrobial agents. Upon detecting these agents, the regulators allow transcription of an appropriate array of resistance markers to counteract the deleterious compounds. Campylobacter jejuni CmeR is a pleiotropic regulator of multiple proteins, including the membrane-bound multidrug efflux transporter CmeABC. CmeR represses the expression of CmeABC and is induced by bile acids, which are substrates of the CmeABC tripartite pump. The multiligand-binding pocket of CmeR has been shown to be very extensive and consists of several positively charged and multiple aromatic amino acids. Here we describe the crystal structures of CmeR in complexes with the bile acids, taurocholate and cholate. Taurocholate and cholate are structurally related, differing by only the anionic charged group. However, these two ligands bind distinctly in the binding tunnel. Taurocholate spans the novel bile acid binding site adjacent to and without overlapping with the previously determined glycerol-binding site. The anionic aminoethanesulfonate group of taurocholate is neutralized by a charge-dipole interaction. Unlike taurocholate, cholate binds in an anti-parallel orientation but occupies the same bile acid-binding site. Its anionic pentanoate moiety makes a water-mediated hydrogen bond with a cationic residue to neutralize the formal negative charge. These structures underscore the promiscuity of the multifaceted binding pocket of CmeR. The capacity of CmeR to recognize bile acids was confirmed using isothermal titration calorimetry and fluorescence polarization. The results revealed that the regulator binds these acids with dissociation constants in the micromolar region. Crystal structures of CmeR-bile acid complexes from Campylobacter jejuni.,Lei HT, Shen Z, Surana P, Routh MD, Su CC, Zhang Q, Yu EW Protein Sci. 2011 Feb 16. doi: 10.1002/pro.602. PMID:21328631 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

Proteopedia Page Contributors and Editors (what is this?)

OCA