TY - JOUR
T1 - Bioactivity studies on atypical natural opioid hexapeptides processed from proenkephalin (PENK) precursor polypeptides
AU - Bojnik, Engin
AU - Kleczkowska, Patrycja
AU - de Velasco, Ezequiel Marron Fernandez
AU - Corbani, Maïthé
AU - Babos, Fruzsina
AU - Lipkowski, Andrzej W.
AU - Magyar, Anna
AU - Benyhe, Sandor
N1 - Funding Information:
This work was supported by TÁMOP — 4.2.2A-11/1KONV-2012-0024 , 2012-052 and OTKA 108518 grants.
PY - 2014/8
Y1 - 2014/8
N2 - Endogenous opioids are derived from four related polypeptide precursors: proenkephalin (PENK), prodynorphin (PDYN), pronociceptin (PNOC) and proopiomelanocortin (POMC). In mammals PENK encodes for four copy of Met-enkephalin, one octapeptide Met-enkephalin-Arg-Gly-Leu, one heptapeptide Met-enkephalin-Arg-Phe and a single copy of Leu-enkephalin. Our detailed bioinformatic search on the existing PENK sequences revealed several atypical hexapeptide Met-enkephalins in different vertebrate animals. They are located either in the second enkephalin unit or in the seventh enkephalin core position at the C-terminus. Altogether four different hexapeptide sequences were obtained representing eleven animal species: Met-enkephalin-Arg6 (YGGFMR) in the bird zebra finch, Met-enkephalin-Asp6 (YGGFMD), Met-enkephalin-Ile6 (YGGFMI) in zebrafish; and Met-enkephalin-Ser6 (YGGFMS) in two pufferfish species. All novel peptides were chemically synthesized and studied in receptor binding and G-protein activation assays performed on rat brain membranes. The four novel enkephalins were equipotent in stimulating G-proteins. Affinities of the peptides determined by equilibrium competition assays in receptor binding experiments were statistically different. At the MOP receptors the highest affinity (Ki 4nM) was obtained with the zebra finch peptide Met-enkephalin-Arg6. The pufferfish Met-enkephalin-Ser6 exhibited the highest affinity (Ki 6.7nM) at the DOP receptor. Phylogenetic neuropeptide libraries, defined here as a collection of mutationally different species variants of orthologous and paralogous peptide sequences, represent the natural molecular diversity of the neuropeptides. Such libraries can provide a wide range of structural information establishing comparative functional analyses. Since DNA sequencing data are rapidly increasing, more development in the natural peptide library concept is expected.
AB - Endogenous opioids are derived from four related polypeptide precursors: proenkephalin (PENK), prodynorphin (PDYN), pronociceptin (PNOC) and proopiomelanocortin (POMC). In mammals PENK encodes for four copy of Met-enkephalin, one octapeptide Met-enkephalin-Arg-Gly-Leu, one heptapeptide Met-enkephalin-Arg-Phe and a single copy of Leu-enkephalin. Our detailed bioinformatic search on the existing PENK sequences revealed several atypical hexapeptide Met-enkephalins in different vertebrate animals. They are located either in the second enkephalin unit or in the seventh enkephalin core position at the C-terminus. Altogether four different hexapeptide sequences were obtained representing eleven animal species: Met-enkephalin-Arg6 (YGGFMR) in the bird zebra finch, Met-enkephalin-Asp6 (YGGFMD), Met-enkephalin-Ile6 (YGGFMI) in zebrafish; and Met-enkephalin-Ser6 (YGGFMS) in two pufferfish species. All novel peptides were chemically synthesized and studied in receptor binding and G-protein activation assays performed on rat brain membranes. The four novel enkephalins were equipotent in stimulating G-proteins. Affinities of the peptides determined by equilibrium competition assays in receptor binding experiments were statistically different. At the MOP receptors the highest affinity (Ki 4nM) was obtained with the zebra finch peptide Met-enkephalin-Arg6. The pufferfish Met-enkephalin-Ser6 exhibited the highest affinity (Ki 6.7nM) at the DOP receptor. Phylogenetic neuropeptide libraries, defined here as a collection of mutationally different species variants of orthologous and paralogous peptide sequences, represent the natural molecular diversity of the neuropeptides. Such libraries can provide a wide range of structural information establishing comparative functional analyses. Since DNA sequencing data are rapidly increasing, more development in the natural peptide library concept is expected.
KW - Enkephalin hexapeptides
KW - Mu and delta opioid receptors
KW - Natural chemical library
KW - Proenkephalin evolution
KW - Species differences
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U2 - 10.1016/j.cbpb.2014.06.002
DO - 10.1016/j.cbpb.2014.06.002
M3 - Article
C2 - 24947211
AN - SCOPUS:84903540253
SN - 1096-4959
VL - 174
SP - 29
EP - 35
JO - Comparative Biochemistry and Physiology Part - B: Biochemistry and Molecular Biology
JF - Comparative Biochemistry and Physiology Part - B: Biochemistry and Molecular Biology
IS - 1
ER -