Scytodecamide from the Cultured Scytonema sp. UIC 10036 Expands the Chemical and Genetic Diversity of Cyanobactins

Abstract

Cyanobactins are a large family of cyanobacterial ribosomally synthesized and post‐translationally modified peptides (RiPPs) often associated with biological activities, such as cytotoxicity, antiviral, and antimalarial activities. They are traditionally described as cyclic molecules containing heterocyclized amino acids. However, this definition has been recently challenged by the discovery of short, linear cyanobactins containing three to five amino acids as well as cyanobactins containing no heterocyclized residues. Herein we report the discovery of scytodecamide (1) from the freshwater cyanobacterium Scytonema sp. UIC 10036. Structural elucidation based on mass spectrometry, 1D and 2D NMR spectroscopy, and Marfey's method revealed 1 to be a linear decapeptide with an N‐terminal N‐methylation and a C‐terminal amidation. The genome of Scytonema sp. UIC 10036 was sequenced, and bioinformatic analysis revealed a cyanobactin‐like biosynthetic gene cluster consistent with the structure of 1. The discovery of 1 as a novel linear peptide containing an N‐terminal N‐methylation and a C‐terminal amidation expands the chemical and genetic diversity of the cyanobactin family of compounds.

Eighteen New Aeruginosamide Variants Produced by the Baltic Cyanobacterium Limnoraphis CCNP1324

“…Thus far, over a hundred cyanobactins have been detected in different free-living and symbiotic cyanobacteria. Amongst others, these compounds have been found and chemically characterized in Anabaena (anacyclamides) [ 24 ], Arthrospira (arthrospiramides) [ 25 ], Lyngbya (aesturamides) [ 26 ], Microcystis (aerucyclamides, aeruginosamides, kawaguchipeptins, microcyclamide, microphycin) [ 15 , 27 , 28 , 29 , 30 ], Scytonema (scytodecamide) [ 31 ] and Sphaerospermopsis (sphaerocyclamides) [ 32 ]. Cyanobactin gene clusters were found in up to 30% of cyanobacteria representing Prochloron , Anabaena , Microcystis , Arthrospira and other genera [ 6 , 7 , 8 , 24 , 33 , 34 ].…”

Antiviral activities and applications of ribosomally synthesized and post-translationally modified peptides (RiPPs)

“…They have traditionally been described as cyclic N-to-C macrocyclized peptides containing heterocyclized amino acids. However, examples of short, linear cyanobactins have also emerged [ 96 ]. Cyanobacterial compounds are often associated with their biological activities, such as cytotoxicity, antimalarial and antiviral activities [ 97 ].…”