Cytochrome c 7: Difference between revisions

Revision as of 09:09, 30 November 2015

GeneralGeneral

Cytocrhome c 7 (Cc7) is a three heme-containing protein derived from the sulfur-reducing bacterium Desulfuromonas acetoxidans. Cc7 is crucial to the bacteria's anaerobic sulfure respiration as it plays a role in the electron-transfer mechanism, and as such it is located in the mitochondrial intermembrane space^[1]. Over the course of 3.5 million years, Desulfuromonas acetoxidans have evolved to use anaerobic sulfure respiration as the main driving force of their survival^[2]. As a result, Cc7 is able to reduce sulfure, its oxidized variants (thiosulfate, sulfur, sulfite, sulfate, etc) and even heavy metals to produce the required energy^[3]. If using sulfure, the product formed is hydrogen sulfide. This compound is able to react with heavy metal ions to form almost non-lethal and quite insoluble metal sulfides^[4]. This enzymatic ability of Cc7 is unique to the animal kingdom, and the ability to create less-toxic and insoluble metal sulfides has intrigued researchers as of late^[5]. By harnessing Desulfuromonas acetoxidans and its Cc7 protein, researchers hope to create possible applications to use these bacteria to decontaminate environments polluted with toxic heavy metals from industrial wastes across the globe. And because of the metal sulfides insolubility, removing them from the environment will be simpler and cheaper than current heavy metal toxic waste filtration operations^[6].

Structural Components

Cc7 is a single polypeptide chain 68 residues total containing three heme groups. The polypeptide strand has one alpha helix 4 residues in length and two beta strands 2 residues in length. The heme groups are labelled as I, III, and IV,

Function

Cc7 is a sulfur terminal reductase, that is, it reduces a sulfur-containing compound into a sulfide to generate electrons to be used in electron transport chain. The steps required to for this to occur are as follows.

First, Cc7 must be in its resting state. Here, Cc7 is fully reduced and the chromium (III) ion is reduced to chromate(-2).

The products of the reaction are chromium(III) and the oxidized protein with three iron(III) hemes.

Structural highlights

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ReferencesReferences

↑ Assfalg M, Bertini I, Bruschi M, Michel C, Turano P. The metal reductase activity of some multiheme cytochromes c: NMR structural characterization of the reduction of chromium(VI) to chromium(III) by cytochrome c(7). 2002; 99(15):9750-4 DOI: 10.1073/pnas.152290999
↑ DOI: 10.1016/s0065-2164(09)01202-7
↑ Pfennig N, Biebl H. Desulfuromonas acetoxidans gen. nov. and sp. nov., a new anaerobic, sulfur-reducing, acetate-oxidizing bacterium. 1976; 110(1): 3-12 DOI: 10.1007/BF00416962
↑ Assfalg M, Bertini I, Bruschi M, Michel C, Turano P. The metal reductase activity of some multiheme cytochromes c: NMR structural characterization of the reduction of chromium(VI) to chromium(III) by cytochrome c(7). 2002; 99(15):9750-4 DOI: 10.1073/pnas.152290999
↑ Pfennig N, Biebl H. Desulfuromonas acetoxidans gen. nov. and sp. nov., a new anaerobic, sulfur-reducing, acetate-oxidizing bacterium. 1976; 110(1): 3-12 DOI: 10.1007/BF00416962
↑ National Service Center for Environmental Publications. [1]

Proteopedia Page Contributors and Editors (what is this?)Proteopedia Page Contributors and Editors (what is this?)

Alexander Douglas, Michal Harel, Alexander Berchansky

[1] Assfalg M, Bertini I, Bruschi M, Michel C, Turano P. The metal reductase activity of some multiheme cytochromes c: NMR structural characterization of the reduction of chromium(VI) to chromium(III) by cytochrome c(7). 2002; 99(15):9750-4 DOI: 10.1073/pnas.152290999

[2] DOI: 10.1016/s0065-2164(09)01202-7

[3] Pfennig N, Biebl H. Desulfuromonas acetoxidans gen. nov. and sp. nov., a new anaerobic, sulfur-reducing, acetate-oxidizing bacterium. 1976; 110(1): 3-12 DOI: 10.1007/BF00416962

[4] Assfalg M, Bertini I, Bruschi M, Michel C, Turano P. The metal reductase activity of some multiheme cytochromes c: NMR structural characterization of the reduction of chromium(VI) to chromium(III) by cytochrome c(7). 2002; 99(15):9750-4 DOI: 10.1073/pnas.152290999

[5] Pfennig N, Biebl H. Desulfuromonas acetoxidans gen. nov. and sp. nov., a new anaerobic, sulfur-reducing, acetate-oxidizing bacterium. 1976; 110(1): 3-12 DOI: 10.1007/BF00416962

[6] National Service Center for Environmental Publications. [1]

[1]

[2]

[3]

[4]

[5]

[6]

@@ Line 2: / Line 2: @@
 <StructureSection load='1LM2.pdb' size='340' side='right' caption='3D Structure of Cytochrome c 7' scene=''>
-'''Cytocrhome c 7''' (Cc7) is a three heme-containing protein derived from the sulfur-reducing bacterium ''Desulfuromonas acetoxidans''. Cc7 is located in the mitochondrial intermembrane space of the bacteria where it plays a role in the electron-transfer mechanism <ref>Assfalg M, Bertini I, Bruschi M, Michel C, Turano P. The metal reductase activity of some multiheme cytochromes c: NMR structural characterization of the reduction of chromium(VI) to chromium(III) by cytochrome c(7). 2002; 99(15):9750-4 '''[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC125002/''' DOI: 10.1073/pnas.152290999''']'''</ref>. ''Desulfuromonas acetoxidans'' bacteria have evolved to obtain their energy from anaerobic sulfure respiration, thus requiring organic disulfide compounds, such as thiosulfate, sulfur, sulfite, or sulfate, as their electron acceptors<ref>Pfennig N, Biebl H. Desulfuromonas acetoxidans gen. nov. and sp. nov., a new anaerobic, sulfur-reducing, acetate-oxidizing bacterium. 1976; 110(1): 3-12 '''[http://link.springer.com/article/10.1007/BF00416962''' DOI: 10.1007/BF00416962''']'''</ref>. This gives Cc7 a very unique ability that interests a lot of researchers as of late: the fact that this protein is able to reduce disulfide compounds down to hydrogen sulfide, which in turn reacts with heavy metal ions to form low-toxicity metal sulfides<ref>Pfennig N, Biebl H. Desulfuromonas acetoxidans gen. nov. and sp. nov., a new anaerobic, sulfur-reducing, acetate-oxidizing bacterium. 1976; 110(1): 3-12 '''[http://link.springer.com/article/10.1007/BF00416962''' DOI: 10.1007/BF00416962''']'''</ref>. To apply this characteristic, researchers hope to create possible applications to use these bacteria in decontamination of environments that are polluted with toxic heavy metals. Because of the insolubility of the metal sulfides, removing them from the environment will be simpler and cheaper than current heavy metal toxic waste filtration operations<ref>National Service Center for Environmental Publications. [http://nepis.epa.gov/Exe/ZyNET.exe/91018HWZ.txt?ZyActionD=ZyDocument&Client=EPA&Index=1976%20Thru%201980&Docs=&Query=&Time=&EndTime=&SearchMethod=1&TocRestrict=n&Toc=&TocEntry=&QField=&QFieldYear=&QFieldMonth=&QFieldDay=&UseQField=&IntQFieldOp=0&ExtQFieldOp=0&XmlQuery=&File=D%3A\ZYFILES\INDEX%20DATA\76THRU80\TXT\00000025\91018HWZ.txt&User=ANONYMOUS&Password=anonymous&SortMethod=h|-&MaximumDocuments=1&FuzzyDegree=0&ImageQuality=r75g8/r75g8/x150y150g16/i425&Display=p|f&DefSeekPage=x&SearchBack=ZyActionL&Back=ZyActionS&BackDesc=Results%20page&MaximumPages=1&ZyEntry=1]</ref>.
+'''Cytocrhome c 7''' (Cc7) is a three heme-containing protein derived from the sulfur-reducing bacterium ''Desulfuromonas acetoxidans''. Cc7 is crucial to the bacteria's anaerobic sulfure respiration as it plays a role in the electron-transfer mechanism, and as such it is located in the mitochondrial intermembrane space<ref>Assfalg M, Bertini I, Bruschi M, Michel C, Turano P. The metal reductase activity of some multiheme cytochromes c: NMR structural characterization of the reduction of chromium(VI) to chromium(III) by cytochrome c(7). 2002; 99(15):9750-4 '''[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC125002/''' DOI: 10.1073/pnas.152290999''']'''</ref>. Over the course of 3.5 million years, ''Desulfuromonas acetoxidans'' have evolved to use anaerobic sulfure respiration as the main driving force of their survival<ref>DOI: 10.1016/s0065-2164(09)01202-7</ref>. As a result, Cc7 is able to reduce sulfure, its oxidized variants (thiosulfate, sulfur, sulfite, sulfate, etc) and even heavy metals to produce the required energy<ref>Pfennig N, Biebl H. Desulfuromonas acetoxidans gen. nov. and sp. nov., a new anaerobic, sulfur-reducing, acetate-oxidizing bacterium. 1976; 110(1): 3-12 '''[http://link.springer.com/article/10.1007/BF00416962''' DOI: 10.1007/BF00416962''']'''</ref>. If using sulfure, the product formed is hydrogen sulfide. This compound is able to react with heavy metal ions to form almost non-lethal and quite insoluble metal sulfides<ref>Assfalg M, Bertini I, Bruschi M, Michel C, Turano P. The metal reductase activity of some multiheme cytochromes c: NMR structural characterization of the reduction of chromium(VI) to chromium(III) by cytochrome c(7). 2002; 99(15):9750-4 '''[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC125002/''' DOI: 10.1073/pnas.152290999''']'''</ref>. This enzymatic ability of Cc7 is unique to the animal kingdom, and the ability to create less-toxic and insoluble metal sulfides has intrigued researchers as of late<ref>Pfennig N, Biebl H. Desulfuromonas acetoxidans gen. nov. and sp. nov., a new anaerobic, sulfur-reducing, acetate-oxidizing bacterium. 1976; 110(1): 3-12 '''[http://link.springer.com/article/10.1007/BF00416962''' DOI: 10.1007/BF00416962''']'''</ref>. By harnessing ''Desulfuromonas acetoxidans'' and its Cc7 protein, researchers hope to create possible applications to use these bacteria to decontaminate environments polluted with toxic heavy metals from industrial wastes across the globe. And because of the metal sulfides insolubility, removing them from the environment will be simpler and cheaper than current heavy metal toxic waste filtration operations<ref>National Service Center for Environmental Publications. [http://nepis.epa.gov/Exe/ZyNET.exe/91018HWZ.txt?ZyActionD=ZyDocument&Client=EPA&Index=1976%20Thru%201980&Docs=&Query=&Time=&EndTime=&SearchMethod=1&TocRestrict=n&Toc=&TocEntry=&QField=&QFieldYear=&QFieldMonth=&QFieldDay=&UseQField=&IntQFieldOp=0&ExtQFieldOp=0&XmlQuery=&File=D%3A\ZYFILES\INDEX%20DATA\76THRU80\TXT\00000025\91018HWZ.txt&User=ANONYMOUS&Password=anonymous&SortMethod=h|-&MaximumDocuments=1&FuzzyDegree=0&ImageQuality=r75g8/r75g8/x150y150g16/i425&Display=p|f&DefSeekPage=x&SearchBack=ZyActionL&Back=ZyActionS&BackDesc=Results%20page&MaximumPages=1&ZyEntry=1]</ref>.
 ==Structural Components==
@@ Line 8: / Line 8: @@
 == Function ==
-Cc7 is a sulfur terminal reductase, that is, it reduces a sulfur-containing compound into a sulfide to generate electrons to be used in electron transport chain.
+Cc7 is a sulfur terminal reductase, that is, it reduces a sulfur-containing compound into a sulfide to generate electrons to be used in electron transport chain. The steps required to for this to occur are as follows.
+First, Cc7 must be in its resting state. Here, Cc7 is fully reduced and the chromium (III) ion is reduced to chromate(-2).
+The products of the reaction are chromium(III) and the oxidized protein with three iron(III) hemes.
 == Structural highlights ==