Tolyporphins–Exotic Tetrapyrrole Pigments in a Cyanobacterium—A Review

• Published in: Molecules (Basel, Switzerland) Vol. 28; no. 16; p. 6132
• Main Authors: Nguyen, Kathy-Uyen, Zhang, Yunlong, Liu, Qihui, Zhang, Ran, Jin, Xiaohe, Taniguchi, Masahiko, Miller, Eric S., Lindsey, Jonathan S.
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 18.08.2023; MDPI
• Subjects: Alcohol; Algae; bacteriochlorin; bioinformatics; Biological activity; Biosynthesis; Chlorophyll; Chromophores; Cyanobacteria; field biology; Kishi, Yoshito; Organisms; Review; Brazil; United Kingdom; Micronesia (Nation); India; Pohnpei
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules28166132

Tolyporphins were discovered some 30 years ago as part of a global search for antineoplastic compounds from cyanobacteria. To date, the culture HT-58-2, comprised of a cyanobacterium–microbial consortium, is the sole known producer of tolyporphins. Eighteen tolyporphins are now known—each is a free base tetrapyrrole macrocycle with a dioxobacteriochlorin (14), oxochlorin (3), or porphyrin (1) chromophore. Each compound displays two, three, or four open β-pyrrole positions and two, one, or zero appended C-glycoside (or –OH or –OAc) groups, respectively; the appended groups form part of a geminal disubstitution motif flanking the oxo moiety in the pyrroline ring. The distinct structures and repertoire of tolyporphins stand alone in the large pigments-of-life family. Efforts to understand the cyanobacterial origin, biosynthetic pathways, structural diversity, physiological roles, and potential pharmacological properties of tolyporphins have attracted a broad spectrum of researchers from diverse scientific areas. The identification of putative biosynthetic gene clusters in the HT-58-2 cyanobacterial genome and accompanying studies suggest a new biosynthetic paradigm in the tetrapyrrole arena. The present review provides a comprehensive treatment of the rich science concerning tolyporphins.