title: Seco[D-Asp3]microcystin-RR and [D-Asp3,D-Glu(OMe)6]microcystin-RR, two new microcystins from a toxic water bloom of the cyanobacterium planktothrixrubescens.
abstract: Two novel microcystins, seco[d-Asp(3)]microcystin-RR (1) and [d-Asp(3),d-Glu(OMe)(6)]-microcystin-RR (2), along with the known [d-Asp(3)]microcystin-RR (3), were isolated from a Planktothrix rubescens toxic bloom collected in Lake Bled, Slovenia. The structures were deduced using one- and two-dimensional NMR techniques, ESIMS/CID/MS analysis, and Marfey's method for determining the amino acids' absolute stereochemistry. Compounds 1 and 3 exhibit weak PP1 inhibitory activity. The NMR data of compound 3 are reported here for the first time.
authors.affiliation: School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv Tel Aviv 69978, Israel.
authors.forename: Olga
authors.initials: O
authors.lastname: Grach-Pogrebinsky
authors.forename: Bojan
authors.initials: B
authors.lastname: Sedmak
authors.forename: Shmuel
authors.initials: S
authors.lastname: Carmeli
mesh_terms: D000595:Amino Acid Sequence; D001427:Bacterial Toxins / Q000737:chemistry*; D000458:Cyanobacteria / Q000737:chemistry*; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D013058:Mass Spectrometry; D052998:Microcystins; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D010456:Peptides, Cyclic / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors*; D017524:Slovenia; D013237:Stereoisomerism
chemical_list: C484208:(D-Asp(3),D-Glu(OMe)(6))microcystin-RR; D001427:Bacterial Toxins; D004791:Enzyme Inhibitors; D052998:Microcystins; D010456:Peptides, Cyclic; C484207:seco(D-Asp(3))microcystin-RR; D010749:Phosphoprotein Phosphatases