View source for 1b5m


==RAT OUTER MITOCHONDRIAL MEMBRANE CYTOCHROME B5==
<StructureSection load='1b5m' size='340' side='right'caption='[[1b5m]], [[Resolution|resolution]] 2.70&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1b5m]] 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=1B5M OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1B5M 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]] 2.7&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=HEM:PROTOPORPHYRIN+IX+CONTAINING+FE'>HEM</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=1b5m FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1b5m OCA], [https://pdbe.org/1b5m PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1b5m RCSB], [https://www.ebi.ac.uk/pdbsum/1b5m PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1b5m ProSAT]</span></td></tr>
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== Function ==
[https://www.uniprot.org/uniprot/CYB5B_RAT CYB5B_RAT] Cytochrome b5 is a membrane bound hemoprotein which function as an electron carrier for several membrane bound oxygenases.
== 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/b5/1b5m_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview03.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=1b5m ConSurf].
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== Publication Abstract from PubMed ==
The role played by the outer mitochondrial membrane (OM) cytochrome b5 heme propionate groups in the electrostatic binding between OM cytochrome b5 and horse heart cytochrome c was investigated by 13C NMR spectroscopy and X-ray crystallography. To achieve these aims, 13C-labeled heme OM cytochrome b5 was expressed in Escherichia coli as previously described [Rivera M., Walker, F.A. (1995) Anal. Biochem. 230, 295-302]. Assignment of the resonances arising from the heme propionate carbons in ferricytochrome b5 was carried out by a combination of one- and two-dimensional NMR experiments. Titrations of [13C]heme-labeled OM cytochrome b5 with horse heart cytochrome c were carried out in order to monitor the resonances arising from the heme propionate carbonyl carbons in OM cytochrome b5. The results from these titrations clearly show that only the heme propionate located on the exposed heme edge in OM cytochrome b5 participates in the electrostatic stabilization of the complex between OM cytochrome b5 and horse heart cytochrome c. Similar experiments carried out monitoring 13C resonances arising from several other heme substituents demonstrated that the stoichiometry of the complex is 1:1. A conditional binding constant, K which equals 3.8 x 10(4) +/- 1.4 x 10(4) at mu = 0.02 M, was obtained for the formation of the complex by fitting the binding curves obtained experimentally to a model based on this stoichiometry. The X-ray crystal structure of rat liver OM cytochrome b5 solved to 2.7 A resolution shows that the structures of bovine liver microsomal cytochrome b5 and rat liver OM cytochrome b5 are almost identical when compared at medium resolution. The similarity between the two structures, combined with the findings that only the heme propionate located on the exposed heme edge of OM cytochrome b5 participates in the electrostatic binding to cytochrome c and that the stability of this complex is similar to that measured for the association between microsomal cytochrome b5 and cytochrome c, clearly indicates that the site of interaction on OM cytochrome b5 is almost identical to the one elucidated for microsomal cytochrome b5. It is therefore possible to conclude that the large body of information gathered by many investigators for the nonphysiological interaction between microsomal cytochrome b5 and cytochrome c (recently reviewed) [Mauk, A. G. Mauk, M. R., Moore, G. R., &amp; Northrup, S. H. (1995) Bioenerg. Biomembr. 27, 311-330] has indeed biological as well as pedagogical validity.

13C NMR spectroscopic and X-ray crystallographic study of the role played by mitochondrial cytochrome b5 heme propionates in the electrostatic binding to cytochrome c.,Rodriguez-Maranon MJ, Qiu F, Stark RE, White SP, Zhang X, Foundling SI, Rodriguez V, Schilling CL 3rd, Bunce RA, Rivera M Biochemistry. 1996 Dec 17;35(50):16378-90. PMID:8973214<ref>PMID:8973214</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 1b5m" style="background-color:#fffaf0;"></div>

==See Also==
*[[Cytochrome b5|Cytochrome b5]]
*[[Cytochrome b5 3D structures|Cytochrome b5 3D structures]]
*[[Hemeproteins|Hemeproteins]]
== References ==
<references/>
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</StructureSection>
[[Category: Large Structures]]
[[Category: Rattus norvegicus]]
[[Category: Rivera M]]
[[Category: White SP]]
[[Category: Zhang X]]