Isolation of New Protein Phosphatase Inhibitors from Two Cyanobacteria Species, Planktothrix spp.

Abstract

Two new protein phosphatase inhibitors, oscillamide B (1) and C (2), were isolated from the cyanobacteria Planktothrix (Oscillatoria) agardhii and P. rubescens. The structures of the inhibitors were elucidated by analysis of HRFABMS, 1D and 2D NMR spectra, and chemical degradation. These inhibitors are ureido-containing cyclic peptides and inhibited serine/threonine protein phosphatases PP1 and PP2A. The inhibitory activities were closely related to the Arg and N-Me-Hty residues in the peptides.

Genetic Variation of Adenylation Domains of the Anabaenopeptin Synthesis Operon and Evolution of Substrate Promiscuity

“…All APs are characterized by a cyclic pentapeptide backbone containing a strictly conserved D-Lys residue in position 2 and N-methylation on the amino acid located in the iϩ1 site from the ε amino group of Lys. Like MCs, AP B and oscillamides B and C have been described as inhibitors of protein phosphatase 1 (PP1) and PP2A (14,41). In contrast, oscillamide Y and schizopeptin have been described as effective inhibitors of serine proteases such as chymotrypsin and trypsin (38,40).…”

Cyanotoxins in inland lakes of the United States: Occurrence and potential recreational health risks in the EPA National Lakes Assessment 2007

“…There are other classes of cyanotoxins that are not well studied, and are therefore not commonly measured such as aeruginosins, anabaenapeptins, other anatoxin analogues, anatoxin-a(s), cyanopeptilins, lyngbyatoxins, microginins, oscillamides, and osillaginins (Sano and Kaya, 1997;Chorus and Bartram, 1999;Erhard et al, 1999;Sano et al, 2001;Welker et al, 2006;Chorus, 2012). In light of the staggering number of toxins, many without commercially available analytical standards or standards of sufficient quality, the prospect of risk assessment becomes staggering and costly, and further contributes to the overall lack of toxicity and epidemiology studies regarding human health.…”

A toxic cyanobacterial bloom in an urban coastal lake, Rio Grande do Sul state, Southern Brazil

“…Anabaenopeptins B and F are the most common compounds among the anabaenopeptin class. They are 19-membered cyclic depsipeptides that possess ureido linkage and have bioactive properties: anabaenopeptin B showed weak relaxation activity to norepinephrine-induced constriction of rat aortic preparations (14) and anabaenopeptin F is an inhibitor of protein phosphatases PP1 and PP2A (37,39).…”