7ou9

Crystal structure of dimeric chlorite dismutase variant Q74E (CCld Q74E) from Cyanothece sp. PCC7425 in complex with nitrite

spinqualitylabelsall models 7ou9, resolution 2.42Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 7ou9 is a 2 chain structure with sequence from Cyanothece sp. PCC 7425. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.42Å Ligands: GOL, HEM, NO2, PGE, SO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function B8HNS6_CYAP4 Publication Abstract from PubMed Chlorite dismutases (Clds) are heme b containing oxidoreductases able to decompose chlorite to chloride and molecular oxygen. This work analyses the impact of the distal, flexible and catalytic arginine on the binding of anionic angulate ligands like nitrite and the substrate chlorite. Dimeric Cld from Cyanothece sp. PCC7425 was used as a model enzyme. We have investigated wild-type CCld having the distal catalytic R127 hydrogen-bonded to glutamine Q74 and variants with R127 (i) being arrested in a salt-bridge with a glutamate (Q74E), (ii) being fully flexible (Q74V) or (iii) substituted by either alanine (R127A) or lysine (R127K). We present the electronic and spectral signatures of the high-spin ferric proteins and the corresponding low-spin nitrite complexes elucidated by UV-visible, circular dichroism and electron paramagnetic resonance spectroscopies. Furthermore, we demonstrate the impact of the dynamics of R127 on the thermal stability of the respective nitrite adducts and present the X-ray crystal structures of the nitrite complexes of wild-type CCld and the variants Q74V, Q74E and R127A. In addition, the molecular dynamics (MD) and the binding modi of nitrite and chlorite to the ferric wild-type enzyme and the mutant proteins and the interaction of the oxoanions with R127 have been analysed by MD simulations. The findings are discussed with respect to the role(s) of R127 in ligand and chlorite binding and substrate degradation. Impact of the dynamics of the catalytic arginine on nitrite and chlorite binding by dimeric chlorite dismutase.,Serra I, Schmidt D, Pfanzagl V, Mlynek G, Hofbauer S, Djinovic-Carugo K, Furtmuller PG, Garcia-Rubio I, Van Doorslaer S, Obinger C J Inorg Biochem. 2021 Dec 10;227:111689. doi: 10.1016/j.jinorgbio.2021.111689. PMID:34922158 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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