View source for 1ib0


==CRYSTAL STRUCTURE OF RAT B5R IN COMPLEX WITH FAD AND NAD==
<StructureSection load='1ib0' size='340' side='right'caption='[[1ib0]], [[Resolution|resolution]] 2.30&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1ib0]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Rattus_norvegicus Rattus norvegicus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1IB0 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1IB0 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]] 2.3&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=FAD:FLAVIN-ADENINE+DINUCLEOTIDE'>FAD</scene>, <scene name='pdbligand=NAD:NICOTINAMIDE-ADENINE-DINUCLEOTIDE'>NAD</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=1ib0 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1ib0 OCA], [https://pdbe.org/1ib0 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1ib0 RCSB], [https://www.ebi.ac.uk/pdbsum/1ib0 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1ib0 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/NB5R3_RAT NB5R3_RAT] Desaturation and elongation of fatty acids, cholesterol biosynthesis, drug metabolism, and, in erythrocyte, methemoglobin reduction.
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/ib/1ib0_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=1ib0 ConSurf].
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== Publication Abstract from PubMed ==
Cytochrome b5 reductase (cb5r) (EC 1.6.6.2) catalyzes the reduction of two molecules of cytochrome b5 using NADH as the physiological electron donor. The structure of pig cb5r at 2.4 A resolution was previously reported in the literature, but it was inconsistent with the biochemistry; for example, K83 and C245 were both implicated in the mechanism, but were not located at the active site. To address this problem, we have determined the structures of cb5r from rat at 2.0 A resolution and in a complex with NAD+ at 2.3 A resolution. We found significant differences throughout the rat structure compared to that of pig, including the locations of the lysine and cysteine residues mentioned above. To test the structural models, we made single amino acid substitutions of this lysine and showed that all substitutions produced correctly folded proteins and exhibited normal flavin behavior. However, the apparent kcat(NADH) decreased, and the apparent K(m) for NADH increased; the K(m)'s for cytochrome b5 were unchanged relative to that of the wild type. The largest effect was for the glutamate-substituted protein, which was further characterized using a charge transfer assay and found to be less efficient at NADH utilization than the wild type. These results are consistent with a role for this lysine in stabilizing the NADH-bound form of cb5r. We have concluded that the pig structure was mistraced in several regions and have reinterpreted mutants in these regions that give rise to the hereditary disease methemoglobinemia.

The structure and biochemistry of NADH-dependent cytochrome b5 reductase are now consistent.,Bewley MC, Marohnic CC, Barber MJ Biochemistry. 2001 Nov 13;40(45):13574-82. PMID:11695905<ref>PMID:11695905</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 1ib0" style="background-color:#fffaf0;"></div>

==See Also==
*[[NADH-cytochrome b5 reductase|NADH-cytochrome b5 reductase]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Rattus norvegicus]]
[[Category: Barber MJ]]
[[Category: Bewley MC]]
[[Category: Marohnic CC]]