MOCS2
Encyclopedia
Molybdenum cofactor synthesis protein 2A and molybdenum cofactor synthesis protein 2B are a pair of protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

s that in humans are encoded from the same MOCS2 gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...

. These two proteins dimerize to form molybdopterin synthase
Molybdopterin synthase
Molybdopterin synthase is an enzyme required to sythesize molybdenum cofactor from precursor Z .It is heterodimeric and coded for by the MOCS2 gene....

.

Function

Eukaryotic molybdoenzymes use a unique molybdenum cofactor
Molybdenum cofactor
Molybdenum cofactor is a cofactor required for the activity of enzymes such as sulfite oxidase, xanthine oxidoreductase, and aldehyde oxidase. It is a coordination complex formed between molybdopterin and an oxide of molybdenum.Molybdopterins, in turn, are synthesized from guanosine triphosphate...

 (MoCo) consisting of a pterin
Pterin
Pterin is a heterocyclic compound composed of a pteridine ring system, with a keto group and an amino group on positions 4 and 2 respectively...

, termed molybdopterin
Molybdopterin
Molybdopterins, when reacted with molybdenum or tungsten in the form of molybdate or tungstate, are a class of cofactors found in most molybdenum and all tungsten enzymes...

, and the catalytically active metal molybdenum
Molybdenum
Molybdenum , is a Group 6 chemical element with the symbol Mo and atomic number 42. The name is from Neo-Latin Molybdaenum, from Ancient Greek , meaning lead, itself proposed as a loanword from Anatolian Luvian and Lydian languages, since its ores were confused with lead ores...

. MoCo is synthesized from precursor Z (now known as cyclic pyranopterin monophosphate
Cyclic pyranopterin monophosphate
Cyclic pyranopterin monophosphate is an experimental treatment for molybdenum cofactor deficiency type A, which was developed by the pioneering work of Jose Santamaría-Araujo, PhD and Prof.Dr...

) by the heterodimeric enzyme molybdopterin synthase
Molybdopterin synthase
Molybdopterin synthase is an enzyme required to sythesize molybdenum cofactor from precursor Z .It is heterodimeric and coded for by the MOCS2 gene....

.

Gene

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
Multicistronic message
Multicistronic message is an archaic term for Polycistronic. Monocistronic, bicistronic and tricistronic are also used to describe mRNA with single, double and triple coding areas ....

 transcript
Transcription (genetics)
Transcription is the process of creating a complementary RNA copy of a sequence of DNA. Both RNA and DNA are nucleic acids, which use base pairs of nucleotides as a complementary language that can be converted back and forth from DNA to RNA by the action of the correct enzymes...

. 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.

The MOCS2 gene contains 7 exons. Exons 1 to 3 encode MOCS2A (the small subunit), and exons 3 to 7 encode MOCS2B (large subunit).

Genetic disease

Defects in both copies of MOCS2 cause the molybdenum cofactor deficiency
Molybdenum cofactor deficiency
Molybdenum cofactor deficiency is a human disease. Absence of molybdenum cofactor leads to accumulation of toxic levels of sulphite and neurological damage usually leading to death within months of birth, due to the lack of active sulfite oxidase...

disease in babies.

Protein Structure

MOCS2A and MOCS2B subunits form dimers in solution. These dimers in turn dimerize to form the tetrameric molybdopterin synthase complex.

Further reading

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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