Journal:Acta Cryst D:S2059798319000676
From Proteopedia
(Difference between revisions)
| Line 4: | Line 4: | ||
<hr/> | <hr/> | ||
<b>Molecular Tour</b><br> | <b>Molecular Tour</b><br> | ||
| - | L-pyroglutamate (pG) is formed by the cyclization of the side chain of glutamate or glutamine amino acid with alpha-amino group at the N-terminus of a polypeptide. This modified residue (pG) cannot be removed by any of the conventional peptidases. Special type of aminopeptidases called pyrrolidone-carboxylate peptidases (PCPs) (EC 3.4.19.-) can remove this unusual amino acid from the peptides or proteins. PCPs are of two types, a) PCPs I, which are cysteine peptidases of C15 family, b) PCPs II are metallopeptidases of M1 family. PCP I is highly conserved enzyme and its homologs have been found from bacteria to human. Many of the physiologically important peptide hormones (TRH, LHRH, GnRH) and antibodies have been shown to possess the pG residue at their N-termini. It seems to have implications in functional regulation of different peptides in both prokaryotes and eukaryotes. However, how these class of enzymes specifically catalyse the removal of pG residue remains mostly unknown. The crystal structures of PCP I from ''Deinococcus radiodurans'' (PCPdr) in its pG-free and pG-bound forms at high resolutions has helped to solve this puzzle. | + | L-pyroglutamate (pG) is formed by the cyclization of the side chain of glutamate or glutamine amino acid with alpha-amino group at the N-terminus of a polypeptide. This modified residue (pG) cannot be removed by any of the conventional peptidases. Special type of aminopeptidases called pyrrolidone-carboxylate peptidases (PCPs) (EC 3.4.19.-) can remove this unusual amino acid from the peptides or proteins. PCPs are of two types, a) PCPs I, which are cysteine peptidases of C15 family, b) PCPs II are metallopeptidases of M1 family. PCP I is highly conserved enzyme and its homologs have been found from bacteria to human. Many of the physiologically important peptide hormones (TRH, LHRH, GnRH) and antibodies have been shown to possess the pG residue at their N-termini. It seems to have implications in functional regulation of different peptides in both prokaryotes and eukaryotes. However, how these class of enzymes specifically catalyse the removal of pG residue remains mostly unknown. The crystal structures of PCP I from ''Deinococcus radiodurans'' (PCPdr) in its pG-free (PDB code [[5z47]]) and pG-bound (PDB code [[5z48]]) forms at high resolutions has helped to solve this puzzle. |
<scene name='80/806393/Cv/23'>Tetrameric structure of PCPdr is shown in cartoon representation</scene>. Each monomer is shown in different color. Bound substrate is shown in magenta spacefill representation. This tetrameric structure is similar to those observed in other PCP I proteins and buries equivalent surfaces of monomers for the formations of the tetramers. | <scene name='80/806393/Cv/23'>Tetrameric structure of PCPdr is shown in cartoon representation</scene>. Each monomer is shown in different color. Bound substrate is shown in magenta spacefill representation. This tetrameric structure is similar to those observed in other PCP I proteins and buries equivalent surfaces of monomers for the formations of the tetramers. | ||
Revision as of 08:36, 10 May 2022
| |||||||||||
This page complements a publication in scientific journals and is one of the Proteopedia's Interactive 3D Complement pages. For aditional details please see I3DC.
