title: Nuclear magnetic resonance (NMR) studies of the dark-color-inducing neurohormone of locusts and corazonin.
abstract: The dark-color-inducing neurohormone (DCIN) of locusts and corazonin of a cockroach, both 11 residue-long peptides, induce dark coloration in albino nymphs of Locusta migratoria when injected after a nymphal molt. These peptides differ at position 7 (His in DCIN and Arg in corazonin) and elicit an almost identical darkening response. The three-dimensional structures of these peptides, dissolved in dimethylsulfoxide (DMSO), were determined by NMR. Structural elements determined at atomic resolution may provide insight into the biological activity of these two neurohormones. The calculated structures of DCIN and corazonin indicate clear, prevalent conformations with similar secondary features. The generated low-energy solution structures of each show structural elements within residues Phe3 to Trp9 with a turn situated at the core of the peptide from which the sidechains of residue 7 of each peptide protrude. A calculated negative electrostatic potential surface almost completely covers both neurohormones and only the 7th residue sidechains of each peptide emerge in their entirety. Within these residues there is a partial sequence seen in several neurohormones that control various physiological functions in Arthropods: -Ser-X-Gly-Trp- (X=His in DCIN and Arg in corazonin). This partial sequence may play a role in the physiological activity of some Arthropod neurohormones.
authors.affiliation: Wolfson Centre for Applied Structural Biology, Silberman Institute of Life Sciences, Safra Campus, Givat Ram, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
authors.forename: Deborah E
authors.initials: DE
authors.lastname: Shalev
authors.forename: Yoram
authors.initials: Y
authors.lastname: Yerushalmi
authors.forename: Meir Paul
authors.initials: MP
authors.lastname: Pener
authors.forename: Irina
authors.initials: I
authors.lastname: Kustanovich
mesh_terms: D000818:Animals; D003118:Color Perception / Q000502:physiology*; D003624:Darkness; D006110:Grasshoppers / Q000235:genetics* / Q000254:growth & development; D007301:Insect Hormones / Q000737:chemistry*; D019476:Insect Proteins; D007814:Larva; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D009479:Neuropeptides / Q000737:chemistry*; D018377:Neurotransmitter Agents / Q000737:chemistry*; D011487:Protein Conformation; D055672:Static Electricity
chemical_list: D007301:Insect Hormones; D019476:Insect Proteins; D009479:Neuropeptides; D018377:Neurotransmitter Agents; C060602:corazonin protein, insect