title: Isolation and structure determination of nostocyclopeptides A1 and A2 from the terrestrial cyanobacterium Nostoc sp. ATCC53789.
abstract: The isolation and total structure determination of nostocyclopeptides A1 (1) and A2 (2) are described. These cyclic heptapeptides, which possess a unique imino linkage in the macrocyclic ring, are characteristic constituents of the cryptophycin-producing cyanobacterium Nostoc sp. ATCC53789. 1D TOCSY experiments proved to be very useful in identifying the seven amino acid residues in each compound, and HMBC and NOESY correlations made it possible to sequence the seven units into a total gross structure. The absolute stereochemistry was determined by directly comparing the amino acids in the acid hydrolyzate of each natural product and its peroxide oxidation and borohydride reduction products with authentic standards. Studies were carried out on the biosynthesis and initiated on the biological activity of these cyclic peptides.
authors.affiliation: Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, USA.
authors.forename: T
authors.initials: T
authors.lastname: Golakoti
authors.forename: W Y
authors.initials: WY
authors.lastname: Yoshida
authors.forename: S
authors.initials: S
authors.lastname: Chaganty
authors.forename: R E
authors.initials: RE
authors.lastname: Moore
mesh_terms: D000903:Antibiotics, Antineoplastic / Q000737:chemistry / Q000302:isolation & purification; D000458:Cyanobacteria / Q000737:chemistry / Q000378:metabolism*; D005612:Freeze Drying; D006801:Humans; D006868:Hydrolysis; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D010084:Oxidation-Reduction; D010456:Peptides, Cyclic / Q000737:chemistry / Q000302:isolation & purification*; D011487:Protein Conformation; D014407:Tumor Cells, Cultured
chemical_list: D000903:Antibiotics, Antineoplastic; D010456:Peptides, Cyclic; C428166:nostocyclopeptide A1; C428167:nostocyclopeptide A2