3vm0

Assimilatory nitrite reductase (Nii3) - N226K mutant - NO2 complex from tobacco leaf

spinqualitylabelsall models 3vm0, resolution 1.70Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3vm0 is a 1 chain structure with sequence from Nicotiana tabacum. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.695Å Ligands: CL, K, NO2, SRM Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q76KB0_TOBAC Publication Abstract from PubMed Assimilatory nitrite reductase (aNiR) reduces nitrite ions (NO$\rm{{_{2}^{-}}}$) to ammonium ions (NH$\rm{{_{4}^{+}}}$), whereas assimilatory sulfite reductase reduces sulfite (SO$\rm{{_{3}^{2-}}}$) to hydrogen sulfide (HS(-) ). Although aNiR can also reduce SO$\rm{{_{3}^{2-}}}$, its activity is much lower than when NO$\rm{{_{2}^{-}}}$ is reduced as the substrate. To increase the SO$\rm{{_{3}^{2-}}}$-reduction activity of aNiR, we performed a N226K mutation of Nii3, a representative aNiR. The resulting Nii3-N226K variant could bind non-native targets, SO$\rm{{_{3}^{2-}}}$, and HCO$\rm{{_{3}^{-}}}$, in addition to its native target, i.e., NO$\rm{{_{2}^{-}}}$. We have determined the high-resolution structure of Nii3-N226K in its apo-state and in complex with SO$\rm{{_{3}^{2-}}}$, NO$\rm{{_{2}^{-}}}$, and HCO$\rm{{_{3}^{-}}}$. This analysis revealed conformational changes of Lys226 and the adjacent Lys224 upon binding of SO$\rm{{_{3}^{2-}}}$, but not NO$\rm{{_{2}^{-}}}$. In contrast, HCO$\rm{{_{3}^{-}}}$ binding induced a conformational change at Arg179. After replacing Asn226 with a positively charged Lys, aNiR showed affinity for several anions. A comparison of all ligand-bound structures for Nii3-N226K revealed that structural changes in the active site depend on the size of the substrate. X-ray crystal structure of a mutant assimilatory nitrite reductase that shows sulfite reductase-like activity.,Nakano S, Takahashi M, Sakamoto A, Morikawa H, Katayanagi K Chem Biodivers. 2012 Sep;9(9):1989-99. doi: 10.1002/cbdv.201100442. PMID:22976986 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Nitrite reductase 3D structures

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