biostudies-literatureXia RNational Institute of Environmental Health SciencesNIEHS NIH HHSAmerican Chemical SocietyCase Western Reserve UniversityNational Science Foundation1950-1957https://www.ebi.ac.uk/biostudies/studies/S-EPMC12418302biostudies-literatureUnknown88(8)Cyanobacterial blooms are a significant environmental concern due to their production of toxic metabolites with potential impacts on ecosystem and human health. Microcystin-LR and microcystin congeners are a major concern with respect to human exposure and intoxication, but there are hundreds of characterized cyanobacterial peptides and metabolites that are of interest for their environmental impact in a variety of classes such as cyanopeptolins/micropeptins, microviridins, microginins, and anabaenopeptins. In this study, we report the isolation and characterization of new micropeptins (<b>1-4</b>), a new ferintoic acid (<b>5</b>) a new microginin (<b>6</b>), and three new microviridins (<b>7-9</b>) from a cyanobacterial bloom sample. The new micropeptins, in particular, exhibited unprecedJournal of natural productsAlteration in Amino Acid Composition and Configuration in Cyanobacterial Peptides Affects Biological Activity.PMC12418302R21ES033758R21 ES0337582320090Solorzano Mahmud AMXie HXia RBertin MJfalseAlteration in Amino Acid Composition and Configuration in Cyanobacterial Peptides Affects Biological Activity.Cyanobacterial blooms are a significant environmental concern due to their production of toxic metabolites with potential impacts on ecosystem and human health. Microcystin-LR and microcystin congeners are a major concern with respect to human exposure and intoxication, but there are hundreds of characterized cyanobacterial peptides and metabolites that are of interest for their environmental impact in a variety of classes such as cyanopeptolins/micropeptins, microviridins, microginins, and anabaenopeptins. In this study, we report the isolation and characterization of new micropeptins (<b>1-4</b>), a new ferintoic acid (<b>5</b>) a new microginin (<b>6</b>), and three new microviridins (<b>7-9</b>) from a cyanobacterial bloom sample. The new micropeptins, in particular, exhibited unpreced2025-01-01T00:00:00Z2025 Aug2026-06-02T17:45:30.102Z2026-05-27T03:07:39.159ZS-EPMC124183024075349810.1021/acs.jnatprod.5c00619