title: Symplocin A, a linear peptide from the Bahamian cyanobacterium Symploca sp. Configurational analysis of N,N-dimethylamino acids by chiral-phase HPLC of naphthacyl esters.
abstract: The absolute stereostructures of the components of symplocin A (3), a new N,N-dimethyl-terminated peptide from the Bahamian cyanobacterium Symploca sp., were assigned from spectroscopic analysis, including MS, 2D NMR, and Marfey's analysis. The complete absolute configuration of symplocin A, including the unexpected D-configurations of the terminal N,N-dimethylisoleucine and valic acid residues, was assigned by chiral-phase HPLC of the corresponding 2-naphthacyl esters, a highly sensitive, complementary strategy for assignment of N-blocked peptide residues where Marfey's method is ineffectual or other methods fall short. Symplocin A exhibited potent activity as an inhibitor of cathepsin E (IC(50) 300 pM).
authors.affiliation: Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0358, United States. tmolinski@ucsd.edu
authors.forename: Tadeusz F
authors.initials: TF
authors.lastname: Molinski
authors.forename: Kirk A
authors.initials: KA
authors.lastname: Reynolds
authors.forename: Brandon I
authors.initials: BI
authors.lastname: Morinaka
mesh_terms: D001444:Bahamas; D020059:Cathepsin E / Q000037:antagonists & inhibitors*; D002851:Chromatography, High Pressure Liquid; D000458:Cyanobacteria / Q000737:chemistry*; D004952:Esters; D020128:Inhibitory Concentration 50; D015394:Molecular Structure; D009281:Naphthalenes / Q000737:chemistry*; D019906:Nuclear Magnetic Resonance, Biomolecular; D010455:Peptides / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology
chemical_list: D004952:Esters; D009281:Naphthalenes; D010455:Peptides; C571950:symplocin A; D020059:Cathepsin E