View source for 3vlx


==Assimilatory nitrite reductase (Nii3) - N226K mutant - ligand free form from tobacco leaf==
<StructureSection load='3vlx' size='340' side='right'caption='[[3vlx]], [[Resolution|resolution]] 1.35&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3vlx]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Nicotiana_tabacum Nicotiana tabacum]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3VLX OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3VLX FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.35&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=K:POTASSIUM+ION'>K</scene>, <scene name='pdbligand=SRM:SIROHEME'>SRM</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=3vlx FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3vlx OCA], [https://pdbe.org/3vlx PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3vlx RCSB], [https://www.ebi.ac.uk/pdbsum/3vlx PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3vlx ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/Q76KB0_TOBAC Q76KB0_TOBAC] 
<div style="background-color:#fffaf0;">
== 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<ref>PMID:22976986</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 3vlx" style="background-color:#fffaf0;"></div>

==See Also==
*[[Nitrite reductase 3D structures|Nitrite reductase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Nicotiana tabacum]]
[[Category: Katayanagi K]]
[[Category: Morikawa H]]
[[Category: Nakano S]]
[[Category: Sakamoto A]]
[[Category: Takahashi M]]