Description

IPR021115 is a Pyridoxal-phosphate binding site.

<p>Pyridoxal phosphate is the active form of vitamin B6 (pyridoxine or pyridoxal). Pyridoxal 5'-phosphate (PLP) is a versatile catalyst, acting as a coenzyme in a multitude of reactions, including decarboxylation, deamination and transamination [[cite:PUB00035505], [cite:PUB00006322], [cite:PUB00035506]]. PLP-dependent enzymes are primarily involved in the biosynthesis of amino acids and amino acid-derived metabolites, but they are also found in the biosynthetic pathways of amino sugars and in the synthesis or catabolism of neurotransmitters; pyridoxal phosphate can also inhibit DNA polymerases and several steroid receptors [[cite:PUB00035507]]. Inadequate levels of pyridoxal phosphate in the brain can cause neurological dysfunction, particularly epilepsy [[cite:PUB00035508]].</p> <p>PLP enzymes exist in their resting state as a Schiff base, the aldehyde group of PLP forming a linkage with the ε-amino group of an active site lysine residue on the enzyme. The α-amino group of the substrate displaces the lysine ε-amino group, in the process forming a new aldimine with the substrate. This aldimine is the common central intermediate for all PLP-catalysed reactions, enzymatic and non-enzymatic [[cite:PUB00035504]].</p> <p>A number of pyridoxal-dependent decarboxylases share regions of sequence similarity, particularly in the vicinity of a conserved lysine residue, which provides the attachment site for the pyridoxal-phosphate (PLP) group [[cite:PUB00001452], [cite:PUB00003414]]. Among these enzymes are aromatic-L-amino-acid decarboxylase (L-dopa decarboxylase or tryptophan decarboxylase), which catalyses the decarboxylation of tryptophan to tryptamine [[cite:PUB00002358]]; tyrosine decarboxylase, which converts tyrosine into tyramine; histidine decarboxylase, which catalyses the decarboxylation of histidine to histamine [[cite:PUB00004715]]; L-aspartate decarboxylase, which converts aspartate to beta-alanine [[cite:PUB00076906]]; and phenylacetaldehyde synthase that catalyses the decarboxylation of L-phenylalanine to 2-phenylethylamine [[cite:PUB00094543]]. These enzymes belong to the group II decarboxylases [[cite:PUB00001452], [cite:PUB00002358]].</p> <p>This signature contains the pyridoxal-phosphate-binding lysine residue. Certain pyridoxal-dependent decarboxylases seem to share regions of sequence similarity [[cite:PUB00003414], [cite:PUB00004715], [cite:PUB00001452], [cite:PUB00002358]], especially in the vicinity of the lysine residue which serves as the attachment site for the pyridoxal-phosphate (PLP) group. These enzymes, known collectively as group II decarboxylases, are:</p> <ul> <li>Glutamate decarboxylase ([ec:4.1.1.15]) (GAD), which catalyses the decarboxylation of glutamate into the neurotransmitter GABA (4-aminobutanoate).</li> <li>Histidine decarboxylase ([ec:4.1.1.22]) (HDC), which catalyses the decarboxylation of histidine to histamine. There are two completely unrelated types of HDC: those that use PLP as a cofactor (found in Gram-negative bacteria and mammals), and those that contain a covalently bound pyruvoyl residue (found in Gram-positive bacteria).</li> <li>Aromatic-L-amino-acid decarboxylase ([ec:4.1.1.28]) (DDC), also known as L-dopa decarboxylase or tryptophan decarboxylase, which catalyses the decarboxylation of tryptophan to tryptamine. It also acts on 5-hydroxy-tryptophan and dihydroxyphenylalanine (L-dopa).</li> <li>Tyrosine decarboxylase ([ec:4.1.1.25]) (TyrDC), which converts tyrosine into tyramine, a precursor of isoquinoline alkaloids and various amides.</li> <li>Cysteine sulphinic acid decarboxylase ([ec:4.1.1.29]).</li> <li>L-2,4-diaminobutyrate decarboxylase ([ec:4.1.1.86]) (DABA decarboxylase).</li> </ul> <p>This entry also includes phenylacetaldehyde synthase and 4-hydroxyphenylacetaldehyde synthase from plants and 3,4-dihydroxyphenylacetaldehyde synthase from insects. Plant aromatic acetaldehyde syntheses (AASs) are effectively indistinguishable from plant aromatic amino acid decarboxylases (AAADs) through primary sequence comparison [[cite:PUB00094588]]. Proteins of the AAAD family are grouped together as a result of their high homology, pyridoxal-5'-phosphate (PLP) dependence, and aromatic substrate requirements [[cite:PUB00094588]]. Similarly 3,4-dihydroxylphenylacetaldehyde (DHPAA) from Aedes aegypti (Yellowfever mosquito) is classified into the aromatic amino acid decarboxylase (AAAD) family based on extremely high sequence homology (about 70%) with dopa decarboxylase (Ddc) but has been shown to catalyse the production of 3,4-dihydroxylphenylacetaldehyde (DHPAA) directly from L-dopa [[cite:PUB00094589]].</p>

This description is obtained from EB-eye REST.

Associated GO terms

GO predictions are based solely on the InterPro-to-GO mappings published by EMBL-EBI, which are in turn based on the mapping of predicted domains to the InterPro dataset. The InterPro-to-GO mapping was last updated on April 27, 2020, while the GO metadata was last updated on April 27, 2020.

Associated Lotus transcripts 24

Co-occuring domains 1

A list of co-occurring predicted domains within the L. japonicus gene space: