6l9s | pdb_00006l9s

Crystal structure of Na-dithionite reduced auracyanin from photosynthetic bacterium Roseiflexus castenholzii

spinqualitylabelsall models 6l9s, resolution 2.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6l9s is a 1 chain structure with sequence from Roseiflexus castenholzii DSM 13941. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2Å Ligands: CU1 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function A7NNM5_ROSCS Publication Abstract from PubMed Auracyanin (Ac) is a blue copper protein that mediates the electron transfer between Alternative Complex III (ACIII) and downstream electron acceptors in both fort chains of filamentous anoxygenic phototrophs. Here, we extracted and purified the air-oxidized RfxAc from the photoheterotrophically grown Roseiflexus castenholzii, and we illustrated the structural basis underlying its electron transferring features. Spectroscopic and enzymatic analyses demonstrated the reduction of air-oxidized RfxAc by the ACIII upon oxidation of menaquinol-4 and menaquinol-7. Crystal structures of the air-oxidized and Na-dithionite-reduced RfxAc at 2.2 and 2.0 A resolutions, respectively, showed that the copper ions are coordinated by His77, His146, Cys141, and Met151 in minor different geometries. The Cu(1)-S(delta) bond length increase of Met151, and the electron density Fourier differences at Cu(1) and His77 demonstrated their essential roles in the dithionite-induced reduction. Structural comparisons further revealed that the RfxAc contains a Chloroflexus aurantiacus Ac-A-like copper binding pocket and a hydrophobic patch surrounding the exposed edge of His146 imidazole, as well as an Ac-B-like Ser- and Thr-rich polar patch located at a different site on the surface. These spectroscopic and structural features allow RfxAc to mediate electron transfers between the ACIII and redox partners different from those of Ac-A and Ac-B. These results provide a structural basis for further investigating the electron transfer and energy transformation mechanism of bacterial photosynthesis, and the diversity and evolution of electron transport chains. Structural basis underlying the electron transfer features of a blue copper protein auracyanin from the photosynthetic bacterium Roseiflexus castenholzii.,Wang C, Xin Y, Min Z, Qi J, Zhang C, Xu X Photosynth Res. 2020 Jan 13. pii: 10.1007/s11120-020-00709-y. doi:, 10.1007/s11120-020-00709-y. PMID:31933173 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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