Pirin, C-terminal

Pirin, C-terminal(InterPro Protein Domain record)

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Pirin, C-terminal

InterPro Protein Domain record

description http://metadb.riken.jp/db/SciNetS_rib124i/prib124u1i

This entry represents C-terminal domain of Pirin proteins from both eukaryotes and prokaryotes.The function of Pirin is unknown but the gene coding for this protein is known to be expressed in all tissues in the human body although it is expressed most strongly in the liver and heart. Pirin is known to be a nuclear protein, exclusively localised within the nucleoplasma and predominantly concentrated within dot-like subnuclear structures [<cite idref="PUB00016051"/>].Pirin is composed of two structurally similar domains arranged face to face. The N-terminal domain additionally features four beta-strands, and the C-terminal domain also includes four additional -strands and a short alpha-helix. Although the two domains are similar, the C-terminal domain of Pirin differs from the N-terminal domain as it does not contain a metal binding site and its sequence does not contain the conserved metal-coordinating residues [<cite idref="PUB00028026"/>]. Pirin is confirmed to be a member of the cupin superfamily on the basis of primary sequence and structural similarity. The presence of a metal binding site in the N-terminal beta-barrel of Pirin, may be significant in its role in regulating NFI DNA replication and NF-kappaB transcription factor activity [<cite idref="PUB00028026"/>].Pirin structure has been found to closely resemble members of the cupin superfamily. Pirin contains the two characteristic sequences of the cupin superfamily, namely PG-(X)5-HXH-(X)4-E-(X)6-G and G-(X)5-PXG-(X)2-H-(X)3-N separated by a variable stretch of 15-50 amino acids. These motifs are best conserved in the N-terminal where the conserved histidine and glutamic acid residues correspond to the metal-coordinating residues. The C-terminal domain motifs lack the metal binding residues normally associated with the cupin fold [<cite idref="PUB00028026"/>]. Pirin was identified to be a metal-binding protein [<cite idref="PUB00020127"/>], and was found that the metal-binding residues of Pirins are highly conserved across mammals, plants, fungi, and prokaryotic organisms. Pirin acts as a cofactor for the transcription factor NFI, the regulatory mechanism of which is generally believed to require the assistance of a metal ion [<cite idref="PUB00028027"/>]. Structural data supports the hypothesis that the bound iron of Pirin may participate in this transcriptional regulation by enhancing and stabilising the formation of the p50,Bcl3,DNA complex [<cite idref="PUB00020127"/>]. Metals have been implicated directly or indirectly in the NF-kappaB family of transcription factors that control expression of a number of early response genes associated with inflammatory responses, cell growth, cell cycle progression, and neoplastic transformation [<cite idref="PUB00028027"/>]. However, most metal-dependent transcription factors are DNA-binding proteins that bind to specific sequences when the metal binds to the protein. Pirin, on the other hand, appears to function differently and bind to the transcription factor DNA complex [<cite idref="PUB00020127"/>].

label http://www.w3.org/2000/01/rdf-schema#label