Molybdenum cofactor synthesis protein 2A and molybdenum cofactor synthesis protein 2B are a pair of proteins that in humans are encoded from the same MOCS2 gene. [5] [6] [7] These two proteins dimerize to form molybdopterin synthase.
Molybdenum cofactor synthesis protein 2A and molybdenum cofactor synthesis protein 2B are a pair of proteins that in humans are encoded from the same MOCS2 gene. [5] [6] [7] These two proteins dimerize to form molybdopterin synthase.
Eukaryotic molybdoenzymes use a unique molybdenum cofactor (MoCo) consisting of a pterin and the catalytically active metal molybdenum. MoCo is synthesized from cyclic pyranopterin monophosphate (precursor Z) by the heterodimeric enzyme molybdopterin synthase. [7]
The large and small subunits of molybdopterin synthase are both encoded from the MOCS2 gene by overlapping open reading frames. The proteins were initially thought to be encoded from a bicistronic transcript. They are now thought to be encoded from monocistronic transcripts. Alternatively spliced transcripts have been found for this locus that encode the large and small subunits. [7]
The MOCS2 gene contains 7 exons. Exons 1 to 3 encode MOCS2A (the small subunit), and exons 3 to 7 encode MOCS2B (large subunit). [5]
Defects in both copies of MOCS2 cause the molybdenum cofactor deficiency disease in babies. [8]
MOCS2A and MOCS2B subunits form dimers in solution. These dimers in turn dimerize to form the tetrameric molybdopterin synthase complex. [9]
Molybdopterins are a class of cofactors found in most molybdenum-containing and all tungsten-containing enzymes. Synonyms for molybdopterin are: MPT and pyranopterin-dithiolate. The nomenclature for this biomolecule can be confusing: Molybdopterin per se contains no molybdenum; rather, this is the name of the ligand that will bind the active metal. After molybdopterin is eventually complexed with molybdenum, the complete ligand is usually called molybdenum cofactor.
Sulfite oxidase is an enzyme in the mitochondria of all eukaryotes, with exception of the yeasts. It oxidizes sulfite to sulfate and, via cytochrome c, transfers the electrons produced to the electron transport chain, allowing generation of ATP in oxidative phosphorylation. This is the last step in the metabolism of sulfur-containing compounds and the sulfate is excreted.
Succinate dehydrogenase complex, subunit A, flavoprotein variant is a protein that in humans is encoded by the SDHA gene. This gene encodes a major catalytic subunit of succinate-ubiquinone oxidoreductase, a complex of the mitochondrial respiratory chain. The complex is composed of four nuclear-encoded subunits and is localized in the mitochondrial inner membrane. SDHA contains the FAD binding site where succinate is deprotonated and converted to fumarate. Mutations in this gene have been associated with a form of mitochondrial respiratory chain deficiency known as Leigh Syndrome. A pseudogene has been identified on chromosome 3q29. Alternatively spliced transcript variants encoding different isoforms have been found for this gene.
Gephyrin is a protein that in humans is encoded by the GPHN gene.
MT-ATP8 is a mitochondrial gene with the full name 'mitochondrially encoded ATP synthase membrane subunit 8' that encodes a subunit of mitochondrial ATP synthase, ATP synthase Fo subunit 8. This subunit belongs to the Fo complex of the large, transmembrane F-type ATP synthase. This enzyme, which is also known as complex V, is responsible for the final step of oxidative phosphorylation in the electron transport chain. Specifically, one segment of ATP synthase allows positively charged ions, called protons, to flow across a specialized membrane inside mitochondria. Another segment of the enzyme uses the energy created by this proton flow to convert a molecule called adenosine diphosphate (ADP) to ATP. Subunit 8 differs in sequence between Metazoa, plants and Fungi.
MT-ATP6 is a mitochondrial gene with the full name 'mitochondrially encoded ATP synthase membrane subunit 6' that encodes the ATP synthase Fo subunit 6. This subunit belongs to the Fo complex of the large, transmembrane F-type ATP synthase. This enzyme, which is also known as complex V, is responsible for the final step of oxidative phosphorylation in the electron transport chain. Specifically, one segment of ATP synthase allows positively charged ions, called protons, to flow across a specialized membrane inside mitochondria. Another segment of the enzyme uses the energy created by this proton flow to convert a molecule called adenosine diphosphate (ADP) to ATP. Mutations in the MT-ATP6 gene have been found in approximately 10 to 20 percent of people with Leigh syndrome.
ATP synthase F1 subunit alpha, mitochondrial is an enzyme that in humans is encoded by the ATP5F1A gene.
Pterin-4-alpha-carbinolamine dehydratase is an enzyme that in humans is encoded by the PCBD1 gene.
Molybdenum cofactor biosynthesis protein 1 is a protein that in humans and other animals, fungi, and cellular slime molds, is encoded by the MOCS1 gene.
NADH dehydrogenase [ubiquinone] iron-sulfur protein 2, mitochondrial (NDUFS2) also known as NADH-ubiquinone oxidoreductase 49 kDa subunit is an enzyme that in humans is encoded by the NDUFS2 gene. The protein encoded by this gene is a core subunit of the mitochondrial membrane respiratory chain NADH dehydrogenase. Mutations in this gene are associated with mitochondrial complex I deficiency.
Phosphorylase b kinase gamma catalytic chain, testis/liver isoform is an enzyme that in humans is encoded by the PHKG2 gene.
Adenylyltransferase and sulfurtransferase MOCS3 is an enzyme that in humans is encoded by the MOCS3 gene.
Molybdenum cofactor deficiency is a rare human disease in which the absence of molybdopterin – and consequently its molybdenum complex, commonly called molybdenum cofactor – leads to accumulation of toxic levels of sulphite and neurological damage. Usually this leads to death within months of birth, due to the lack of active sulfite oxidase. Furthermore, a mutational block in molybdenum cofactor biosynthesis causes absence of enzyme activity of xanthine dehydrogenase/oxidase and aldehyde oxidase.
Molybdopterin synthase (EC 2.8.1.12, MPT synthase) is an enzyme required to synthesize molybdopterin (MPT) from precursor Z (now known as cyclic pyranopterin monophosphate). Molydopterin is subsequently complexed with molybdenum to form molybdenum cofactor (MoCo). MPT synthase catalyses the following chemical reaction:
Molybdopterin adenylyltransferase is an enzyme with systematic name ATP:molybdopterin adenylyltransferase. This enzyme catalyses the following chemical reaction
Molybdenum cofactor cytidylyltransferase is an enzyme with systematic name CTP:molybdenum cofactor cytidylyltransferase. This enzyme catalyses the following chemical reaction:
Molybdopterin-synthase adenylyltransferase is an enzyme with systematic name ATP:molybdopterin-synthase adenylyltransferase. This enzyme catalyses the following chemical reaction
Molybdopterin synthase sulfurtransferase is an enzyme with systematic name persulfurated L-cysteine desulfurase:(molybdopterin-synthase sulfur-carrier protein)-Gly-Gly sulfurtransferase. This enzyme catalyses the following chemical reaction
Cyclic pyranopterin monophosphate synthase is an enzyme with systematic name GTP 8,9-lyase . This enzyme catalyses the following chemical reaction
Transmembrane protein 70 is a protein that in humans is encoded by the TMEM70 gene. It is a transmembrane protein located in the mitochondrial inner membrane involved in the assembly of the F1 and Fo structural subunits of ATP synthase. Mutations in this gene have been associated with neonatal mitochondrial encephalo-cardiomyopathy due to ATP synthase deficiency, causing a wide variety of symptoms including 3-methylglutaconic aciduria, lactic acidosis, mitochondrial myopathy, and cardiomyopathy.
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