title: The study of solution conformation of allatostatins by 2-D NMR and molecular modeling.
abstract: More than 70 allatostatins have been isolated from various insects and there is interest in the determination of their active conformation. We have synthesized Dippu-AST 1 (originally isolated from the cockroach Blattella germanica) and studied its conformation in solution by 2-D NMR and molecular modeling. Dippu-AST 1 belongs to the cockroach-type ASTs that have Y/FXFGL-NH(2) as the common C-terminal sequence. We found that Dippu-AST 1 forms a type I' beta-turn conformation in DMSO. We also studied the conformations of Dippu-AST 1 and six cockroach-type allatostatins in water using the molecular dynamics method. When the X amino acid in the consensus sequence Y/FXFGL-NH(2) is Ala or Ser, the allatostatin can form a typical type II beta-turn. If the X is Asp or Asn whose side chain contains a carbonyl, the allatostatin can form a type I, I' or IV beta-turn conformation; if the X is Gly, a closer gamma-turn is adopted. Our study indicates that the turn conformation is ubiquitous in cockroach-type allatostatins.
authors.affiliation: Department of Applied Chemistry, College of Science, China Agricultural University, Beijing 100094, PR China.
authors.forename: Zhen-peng
authors.initials: ZP
authors.lastname: Kai
authors.forename: Yun
authors.initials: Y
authors.lastname: Ling
authors.forename: Wen-jun
authors.initials: WJ
authors.lastname: Liu
authors.forename: Fei
authors.initials: F
authors.lastname: Zhao
authors.forename: Xin-ling
authors.initials: XL
authors.lastname: Yang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003058:Cockroaches / Q000737:chemistry; D007301:Insect Hormones / Q000737:chemistry; D008958:Models, Molecular; D009479:Neuropeptides / Q000737:chemistry*; D019906:Nuclear Magnetic Resonance, Biomolecular; D011487:Protein Conformation; D012996:Solutions; D013816:Thermodynamics
chemical_list: D007301:Insect Hormones; D009479:Neuropeptides; D012996:Solutions; C076523:allatostatin; C061164:allatostatin 1