title: A cyclic side-chain-linked biphenyl ether tripeptide: H3N(+)-cyclo-[Phe(4-O)Phe-Phe(3-O)]-OMe.Cl-.
abstract: The crystal structure of the chloride salt of H3N(+)-cyclo-(Phe(4-O)-Phe-Phe(3-O)-OMe, cyclo-phenylalanyl-phenylalanyl-phenylalaninium chloride methyl esther, C28H30N3O5+.Cl(-), is described. It is oxidatively linked through a biaryl ether linkage formed from the hydroxyl of 4-hydroxyphenylalanine and the meta position of the distal phenylalanine residue. This is the first reported crystal-structure determination of a cyclic 17-membered biphenyl ether tripeptide, a class which includes the natural products K-13 and OF4949 I-IV. An unusual C-H...O hydrogen bond is formed between the methine H atom of the N-terminal C alpha and a carbonyl-O atom of a neighboring molecule [C...O = 2.995 (4) A].
authors.affiliation: Department of Chemistry and School of Pharmacy, University of Wisconsin-Madison 53706, USA.
authors.forename: J W
authors.initials: JW
authors.lastname: Janetka
authors.forename: K A
authors.initials: KA
authors.lastname: Satyshur
authors.forename: D H
authors.initials: DH
authors.lastname: Rich
mesh_terms: D018360:Crystallography, X-Ray; D006860:Hydrogen Bonding; D010456:Peptides, Cyclic / Q000737:chemistry*; D011487:Protein Conformation
chemical_list: D010456:Peptides, Cyclic