Sulfide quinone oxidoreductase
From Proteopedia
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==Introduction to SQOR== | ==Introduction to SQOR== | ||
| - | Oxidoreductases are used to catalyze the movement of electrons between an oxidant and a reductant. '''Sulfide quinone oxidoreductase''', <scene name='88/881543/Sqor_-_1/1'>SQOR</scene>, is an integral membrane protein used in the mitochondria during metabolism to oxidize hydrogen sulfide with assistance from a quinone <ref name="jackson 1">PMID:30905673</ref>. This enzyme marks the committed step of the sulfide oxidation pathway. SQOR is also the enzyme involved in the irreversible step of hydrogen sulfide metabolism <ref name="landry">PMID:31591036</ref>. In the environment, sulfide is found in aquatic marine environments and in soil but is typically produced by prokaryotes and eukaryotes through catabolism <ref name="lencina">PMID:23103448</ref>. SQOR uses coenzyme Q as the electron acceptor, and it uses sulfide, sulfite, cyanide, or glutathione as a sulfane acceptor <ref name="SQOR-1">PMID:22852582</ref>. Sulfane, or thiosulfoxide sulfur, is an essential molecule in the regulation of cellular processes. It has the capabilities to create cofactors as well as modify enzymatic activities <ref name="toohey">PMID:25153879</ref>. Coenzyme Q is essential for electron transfer in metabolic processes, anabolic and catabolic. In bacterial SQOR, cytochrome C is used as the electron acceptor <ref name="jackson 1" />. The gasotransmitter, hydrogen sulfide or H2S, acts in biological processes and can be used as a target in drug interactions, which can be observed in mitochondrial metabolism <ref name="jackson 1">PMID:30905673</ref>. Hydrogen sulfide signaling is used in the cardiovascular system to prevent the development of cardiovascular diseases, such as hypertension <ref name="jackson 1"/>. SQOR can also be found in bacteria, producing sulfane sulfur metabolites <ref name="jackson 1">PMID:30905673</ref>. In contrast to human SQOR, it does not use a sulfane acceptor. In humans, SQOR belongs to the flavoprotein disulfide reductase (FDR) family (Miller, 2013). SQOR is also in the pyridine nucleotide- disulfide oxidoreductase family. There are also various types of SQORs found, such as SqrA, SqrB, SqrC, SqrD, SqrE, and SqrF <ref name="lencina">PMID:23103448</ref>. The crystallization method used on this SQOR was vapor diffusion at a pH of 7, which in result, gave indicators of the length and structure of this monumental enzyme. | + | Oxidoreductases are used to catalyze the movement of electrons between an oxidant and a reductant. '''Sulfide quinone oxidoreductase''' or '''Sulfide:quinone oxidoreductase''', <scene name='88/881543/Sqor_-_1/1'>SQOR</scene>, is an integral membrane protein used in the mitochondria during metabolism to oxidize hydrogen sulfide with assistance from a quinone <ref name="jackson 1">PMID:30905673</ref>. This enzyme marks the committed step of the sulfide oxidation pathway. SQOR is also the enzyme involved in the irreversible step of hydrogen sulfide metabolism <ref name="landry">PMID:31591036</ref>. In the environment, sulfide is found in aquatic marine environments and in soil but is typically produced by prokaryotes and eukaryotes through catabolism <ref name="lencina">PMID:23103448</ref>. SQOR uses coenzyme Q as the electron acceptor, and it uses sulfide, sulfite, cyanide, or glutathione as a sulfane acceptor <ref name="SQOR-1">PMID:22852582</ref>. Sulfane, or thiosulfoxide sulfur, is an essential molecule in the regulation of cellular processes. It has the capabilities to create cofactors as well as modify enzymatic activities <ref name="toohey">PMID:25153879</ref>. Coenzyme Q is essential for electron transfer in metabolic processes, anabolic and catabolic. In bacterial SQOR, cytochrome C is used as the electron acceptor <ref name="jackson 1" />. The gasotransmitter, hydrogen sulfide or H2S, acts in biological processes and can be used as a target in drug interactions, which can be observed in mitochondrial metabolism <ref name="jackson 1">PMID:30905673</ref>. Hydrogen sulfide signaling is used in the cardiovascular system to prevent the development of cardiovascular diseases, such as hypertension <ref name="jackson 1"/>. SQOR can also be found in bacteria, producing sulfane sulfur metabolites <ref name="jackson 1">PMID:30905673</ref>. In contrast to human SQOR, it does not use a sulfane acceptor. In humans, SQOR belongs to the flavoprotein disulfide reductase (FDR) family (Miller, 2013). SQOR is also in the pyridine nucleotide- disulfide oxidoreductase family. There are also various types of SQORs found, such as SqrA, SqrB, SqrC, SqrD, SqrE, and SqrF <ref name="lencina">PMID:23103448</ref>. The crystallization method used on this SQOR was vapor diffusion at a pH of 7, which in result, gave indicators of the length and structure of this monumental enzyme. |
<StructureSection load='6oi5' size='340' side='right' caption='Human sulphide quinone oxidoreductase complex with FAD (PDB code [[6oi5]])' scene=''> | <StructureSection load='6oi5' size='340' side='right' caption='Human sulphide quinone oxidoreductase complex with FAD (PDB code [[6oi5]])' scene=''> | ||
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The FAD binding site on SQOR is a significant landmark in SQOR. FAD is <scene name='88/881543/Fad_-_1/1'>flavin adenine dinucleotide</scene> and is a product of condensation reaction between adenine diphosphate and riboflavin. There are about eleven FAD-binding locations on sulfide quinone oxidoreductase. FAD-binding involves twelve hydrogen bonds to the enzyme, with an addition of interactions with dipoles electrostatically <ref name="jackson 1" />. It is important to note that Lys207 and Lys418 are located near FAD’s binding location, and they are both relatively basic residues. There are also two additional lysine residues at 200 and 344 that are located by the ribityl chain on the FAD <ref name="jackson 1" />. Ribityl chains occur when a terminal hydroxyl group is removed. To help stabilize the charge of the flavin ring, the N-terminus on alpha helix 11 is positioned towards the FAD ring. In addition, alpha helix 1 helps neutralize the charge of the FAD <ref name="jackson 1" />. On the surface of SQOR that is facing the membrane, there is an entrance which leads to the CoQ-binding pocket. Coenzyme Q is very prevalent within cell membranes. This lipid electron transporter, as previously mentioned, is important in SQOR’s pathway to metabolize hydrogen sulfide <ref name="jackson 1" />. Decreased prevalence of coenzyme Q affects the oxidation of hydrogen sulfide, and can cause skin fibroblasts in humans, as recently studied <ref name="quinzii" />. | The FAD binding site on SQOR is a significant landmark in SQOR. FAD is <scene name='88/881543/Fad_-_1/1'>flavin adenine dinucleotide</scene> and is a product of condensation reaction between adenine diphosphate and riboflavin. There are about eleven FAD-binding locations on sulfide quinone oxidoreductase. FAD-binding involves twelve hydrogen bonds to the enzyme, with an addition of interactions with dipoles electrostatically <ref name="jackson 1" />. It is important to note that Lys207 and Lys418 are located near FAD’s binding location, and they are both relatively basic residues. There are also two additional lysine residues at 200 and 344 that are located by the ribityl chain on the FAD <ref name="jackson 1" />. Ribityl chains occur when a terminal hydroxyl group is removed. To help stabilize the charge of the flavin ring, the N-terminus on alpha helix 11 is positioned towards the FAD ring. In addition, alpha helix 1 helps neutralize the charge of the FAD <ref name="jackson 1" />. On the surface of SQOR that is facing the membrane, there is an entrance which leads to the CoQ-binding pocket. Coenzyme Q is very prevalent within cell membranes. This lipid electron transporter, as previously mentioned, is important in SQOR’s pathway to metabolize hydrogen sulfide <ref name="jackson 1" />. Decreased prevalence of coenzyme Q affects the oxidation of hydrogen sulfide, and can cause skin fibroblasts in humans, as recently studied <ref name="quinzii" />. | ||
| + | ==3D structures of sulfide quinone oxidoreductase== | ||
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| + | [[3D structures of sulfide quinone oxidoreductase]] | ||
| - | </StructureSection> | ||
== References == | == References == | ||
<references/> | <references/> | ||
| + | [[Category:Topic Page]] | ||
Current revision
Contents |
Introduction to SQOR
Oxidoreductases are used to catalyze the movement of electrons between an oxidant and a reductant. Sulfide quinone oxidoreductase or Sulfide:quinone oxidoreductase, , is an integral membrane protein used in the mitochondria during metabolism to oxidize hydrogen sulfide with assistance from a quinone [1]. This enzyme marks the committed step of the sulfide oxidation pathway. SQOR is also the enzyme involved in the irreversible step of hydrogen sulfide metabolism [2]. In the environment, sulfide is found in aquatic marine environments and in soil but is typically produced by prokaryotes and eukaryotes through catabolism [3]. SQOR uses coenzyme Q as the electron acceptor, and it uses sulfide, sulfite, cyanide, or glutathione as a sulfane acceptor [4]. Sulfane, or thiosulfoxide sulfur, is an essential molecule in the regulation of cellular processes. It has the capabilities to create cofactors as well as modify enzymatic activities [5]. Coenzyme Q is essential for electron transfer in metabolic processes, anabolic and catabolic. In bacterial SQOR, cytochrome C is used as the electron acceptor [1]. The gasotransmitter, hydrogen sulfide or H2S, acts in biological processes and can be used as a target in drug interactions, which can be observed in mitochondrial metabolism [1]. Hydrogen sulfide signaling is used in the cardiovascular system to prevent the development of cardiovascular diseases, such as hypertension [1]. SQOR can also be found in bacteria, producing sulfane sulfur metabolites [1]. In contrast to human SQOR, it does not use a sulfane acceptor. In humans, SQOR belongs to the flavoprotein disulfide reductase (FDR) family (Miller, 2013). SQOR is also in the pyridine nucleotide- disulfide oxidoreductase family. There are also various types of SQORs found, such as SqrA, SqrB, SqrC, SqrD, SqrE, and SqrF [3]. The crystallization method used on this SQOR was vapor diffusion at a pH of 7, which in result, gave indicators of the length and structure of this monumental enzyme.
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