Microviridin

File:Microviridin B.png

The microviridins are a class of serine protease inhibitors produced by various genera of cyanobacteria. Recent genome mining has shown that the biosynthetic gene cluster responsible for microviridin biosynthesis is much more prevalent, found in many species of Pseudomonadota (formerly Proteobacteria) and Bacteriodota (formerly Bacteriodetes).{{cite journal |vauthors=Ahmed MN, Reyna-González E, Schmid B, Wiebach V, Süssmuth RD, Dittmann E, Fewer DP |title=Phylogenomic Analysis of the Microviridin Biosynthetic Pathway Coupled with Targeted Chemo-Enzymatic Synthesis Yields Potent Protease Inhibitors |journal=ACS Chem. Biol. |volume= 12|issue= 6|pages= 1538–1546|year=2017 |pmid=28406289 |doi=10.1021/acschembio.7b00124 }}

Microviridins are members of the RiPP family of natural products.

The first microviridin was isolated from Microcystis viridis (NIES-102) and its structure was reported in 1990.Ishitsuka MO, Kusumi T, Kakisawa H, Kunimitsu K, Watanabe MM (1990). “Microviridin. A novel tricyclic depsipeptide from the toxic cyanobacterium Microsystis viridis”. J. Am. Chem. Soc. 112 (22): 8180-8182. doi: 10.1021/ja00178a060.

Microviridins are characterized by a tricyclic depsipeptide structure resulting from the enzymatic activity of two dedicated ATP-grasp ligases, which form two lactone and one lactam rings in the core region of the precursor peptide.{{cite journal |vauthors=Ziemert N, Ishida K, Liaimer A, Hertweck C, Dittmann E |title=Ribosomal synthesis of tricyclic depsipeptides in bloom-forming cyanobacteria |journal=Angew. Chem. Int. Ed. Engl. |volume=47 |issue=40 |pages=7756–9 |year=2008 |pmid=18683268 |doi=10.1002/anie.200802730 }}{{cite journal |vauthors=Philmus B, Christiansen G, Yoshida WY, Hemscheidt TK |title=Post-translational modification in microviridin biosynthesis |journal=ChemBioChem |volume=9 |issue=18 |pages=3066–73 |year=2008 |pmid=19035375 |doi=10.1002/cbic.200800560 |doi-access=free }}