InterPro domain: IPR000183

Pyridoxal-dependent decarboxylases acting on ornithine, lysine, arginine and related substrates can be classified into two different families on the basis of sequence similarities [ 1 , 2 ]. Members of this family while most probably evolutionary related, do not share extensive regions of sequence similarities. PLP-dependent decarboxylases exhibit two different structural folds, Fold I and Fold III. This family belong to the Fold III group which proceed with retention of configuration at the site of decarboxylation, with the exception of diaminopimelate decarboxylase (DAPDC) and D-ornithine/D-lysine decarboxylase (DOKDC) from Salmonella enterica serovar typhimurium, that are known as stereoinverting decarboxylases [ 3 ]. The proteins contain a conserved lysine residue which is known, in mouse ODC [ 4 ], to be the site of attachment of the pyridoxal-phosphate group and it is thought to be responsible for protonation of the product, thus resulting in the retention of configuration for decarboxylation of l-amino acids and inversion for decarboxylation of d-amino acids [ 5 ]. The proteins also contain a stretch of three consecutive glycine residues and has been proposed to be part of a substrate-binding region [ 5 ].

These enzymes are collectively known as group IV decarboxylases, and include ornithine and arginine decarboxylases, and diaminopimelate decarboxylase (DAP) [ 6 ].

1. Pseudomonas aeruginosa diaminopimelate decarboxylase: evolutionary relationship with other amino acid decarboxylases. Mol. Biol. Evol. 5, 549-59
2. Multiple evolutionary origin of pyridoxal-5'-phosphate-dependent amino acid decarboxylases. Eur. J. Biochem. 221, 997-1002
3. Crystal Structure of d-Ornithine/d-Lysine Decarboxylase, a Stereoinverting Decarboxylase: Implications for Substrate Specificity and Stereospecificity of Fold III Decarboxylases. Biochemistry 58, 1038-1042
4. Mechanism of the irreversible inactivation of mouse ornithine decarboxylase by alpha-difluoromethylornithine. Characterization of sequences at the inhibitor and coenzyme binding sites. J. Biol. Chem. 267, 150-8
5. Nucleotide sequence and analysis of the speA gene encoding biosynthetic arginine decarboxylase in Escherichia coli. J. Bacteriol. 172, 4631-40