posted on 2019-09-11, 13:35authored byDaniel Braga, Daniel Last, Mahmudul Hasan, Huijuan Guo, Daniel Leichnitz, Zerrin Uzum, Ingrid Richter, Felix Schalk, Christine Beemelmanns, Christian Hertweck, Gerald Lackner
Coenzyme
F420 is a specialized redox cofactor with a negative redox
potential. It supports biochemical processes like methanogenesis,
degradation of xenobiotics, and the biosynthesis of antibiotics. Although
well-studied in methanogenic archaea and actinobacteria, not much
is known about F420 in Gram-negative bacteria. Genome sequencing
revealed F420 biosynthetic genes in the Gram-negative,
endofungal bacterium Paraburkholderia rhizoxinica, a symbiont of phytopathogenic fungi. Fluorescence microscopy, high-resolution
LC-MS, and structure elucidation by NMR demonstrated that the encoded
pathway is active and yields unexpected derivatives of F420 (3PG-F420). Further analyses of a biogas-producing microbial
community showed that these derivatives are more widespread in nature.
Genetic and biochemical studies of their biosynthesis established
that a specificity switch in the guanylyltransferase CofC reprogrammed
the pathway to start from 3-phospho-d-glycerate, suggesting
a rerouting event during the evolution of F420 biosynthesis.
Furthermore, the cofactor activity of 3PG-F420 was validated,
thus opening up perspectives for its use in biocatalysis. The 3PG-F420 biosynthetic gene cluster is fully functional in Escherichia coli, enabling convenient production of the
cofactor by fermentation.