crystal structure of thermotoga maritima s-adenosylmethionine decarboxylase
Adenosylmethionine decarboxylase is an enzyme that catalyzes the conversion of S-adenosyl methionine to S-adenosylmethioninamine.
Polyamines such as spermidine and spermine are essential for cellular growth under most conditions, being implicated in a large number of cellular processes including DNA, RNA and protein synthesis. S-adenosylmethionine decarboxylase (AdoMetDC) plays an essential regulatory role in the polyamine biosynthetic pathway by generating the n-propylamine residue required for the synthesis of spermidine and spermine from putrescein. Unlike many amino acid decarboxylases AdoMetDC uses a covalently bound pyruvate residue as a cofactor rather than the more common pyridoxal 5'-phosphate. These proteins can be divided into two main groups which show little sequence similarity either to each other, or to other pyruvoyl-dependent amino acid decarboxylases: class I enzymes found in bacteria and archaea, and class II enzymes found in eukaryotes. In both groups the active enzyme is generated by the post-translational autocatalytic cleavage of a precursor protein. This cleavage generates the pyruvate precursor from an internal serine residue and results in the formation of two non-identical subunits termed alpha and beta which form the active enzyme.
- ^ van Poelje PD, Snell EE (1990). "Pyruvoyl-dependent enzymes". Annu. Rev. Biochem. 59: 29–59. doi:10.1146/annurev.bi.59.070190.000333. PMID 2197977.
- ^ Pegg AE, Xiong H, Feith DJ, Shantz LM (November 1998). "S-adenosylmethionine decarboxylase: structure, function and regulation by polyamines". Biochem. Soc. Trans. 26 (4): 580–6. PMID 10047786.