title: Peptide leucine arginine, a potent immunomodulatory peptide isolated and structurally characterized from the skin of the Northern Leopard frog, Rana pipiens.
abstract: On the basis of histamine release from rat peritoneal mast cells, an octadecapeptide was isolated from the skin extract of the Northern Leopard frog (Rana pipiens). This peptide was purified to homogeneity using reversed-phase high performance liquid chromatography and found to have the following primary structure by Edman degradation and pyridylethylation: LVRGCWTKSYPPKPCFVR, in which Cys(5) and Cys(15) are disulfide bridged. The peptide was named peptide leucine-arginine (pLR), reflecting the N- and C-terminal residues. Molecular modeling predicted that pLR possessed a rigid tertiary loop structure with flexible end regions. pLR was synthesized and elicited rapid, noncytolytic histamine release that had a 2-fold greater potency when compared with one of the most active histamine-liberating peptides, namely melittin. pLR was able to permeabilize negatively charged unilamellar lipid vesicles but not neutral vesicles, a finding that was consistent with its nonhemolytic action. pLR inhibited the early development of granulocyte macrophage colonies from bone marrow stem cells but did not induce apoptosis of the end stage granulocytes, i.e. mature neutrophils. pLR therefore displays biological activity with both granulopoietic progenitor cells and mast cells and thus represents a novel bioactive peptide from frog skin.
authors: Departments of Medicine, The Queen's University of Belfast, Belfast BT12 6BJ, United Kingdom.
authors: A L
authors: AL
authors: Salmon
authors: L J
authors: LJ
authors: Cross
authors: A E
authors: AE
authors: Irvine
authors: T R
authors: TR
authors: Lappin
authors: M
authors: M
authors: Dathe
authors: G
authors: G
authors: Krause
authors: P
authors: P
authors: Canning
authors: L
authors: L
authors: Thim
authors: M
authors: M
authors: Beyermann
authors: S
authors: S
authors: Rothemund
authors: M
authors: M
authors: Bienert
authors: C
authors: C
authors: Shaw
mesh_terms: D000276:Adjuvants, Immunologic / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D000595:Amino Acid Sequence; D000818:Animals; D001120:Arginine / Q000737:chemistry* / Q000302:isolation & purification; D002118:Calcium / Q000378:metabolism; D002847:Chromatography, Agarose; D002851:Chromatography, High Pressure Liquid; D002942:Circular Dichroism; D003545:Cysteine / Q000737:chemistry; D016208:Databases, Factual; D004305:Dose-Response Relationship, Drug; D006632:Histamine / Q000378:metabolism; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D007930:Leucine / Q000737:chemistry* / Q000302:isolation & purification; D008407:Mast Cells / Q000378:metabolism; D008555:Melitten / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009504:Neutrophils / Q000378:metabolism; D010452:Peptide Biosynthesis; D010455:Peptides / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D011485:Protein Binding; D011487:Protein Conformation; D011894:Rana pipiens; D020539:Sequence Analysis, Protein; D012867:Skin / Q000737:chemistry; D013696:Temperature; D013997:Time Factors
chemical_list: D000276:Adjuvants, Immunologic; D010455:Peptides; C425308:peptide leucine arginine; D008555:Melitten; D006632:Histamine; D001120:Arginine; D007770:L-Lactate Dehydrogenase; D007930:Leucine; D003545:Cysteine; D002118:Calcium