Table 2.
Functionally characterized F420-reducing dehydrogenases. This table updates and expands upon the enzymes previously summarized and reviewed by Greening et al. (2016).
| Oxidoreductase and domain | Physiological role | Taxonomic distribution | Family | EC no. | PDB ID | References |
|---|---|---|---|---|---|---|
| Archaea | ||||||
| Frh: F420-reducing hydrogenase | Methanogenic growth on H2. Couples oxidation of H2 to the reduction of F420. May be physiologically reversible. | All orders of methanogens | FDRC | 1.12.98.1 | 4OMF, 4CI0, 3ZFS, 6QGT | Tzeng, Wolfe and Bryant (1975); Jacobson et al. (1982); Muth, Morschel and Klein (1987); Kulkarni et al. (2009); Mills et al. (2013); Allegretti et al. (2014); Vitt et al. (2014); Ilina et al. (2019) |
| Ffd: F420-reducing formate dehydrogenase | Methanogenic growth on formate. Couples oxidation of formate to the reduction of F420. May be part of electron-bifurcating complex. | Many Euryarchaeota (e.g. Methanobacteriales, Methanococcales, Methanopyrales, Methanomicrobiales and Methanocellales) | FDRC | 1.2.99.9 | Jones and Stadtman (1981); Schauer and Ferry (1986); Costa et al. (2010); Tzeng, Wolfe and Bryant (1975); Wood, Haydock and Leigh (2003) | |
| Adf: F420-reducing secondary alcohol dehydrogenase | Growth on secondary alcohols. Couples oxidation of secondary alcohols (e.g. isopropanol) to the reduction of F420. | Some Euryarchaeota (Methanomicrobiales and Methanocellales) | LLHT | 1.1.98.5 | 1RHC | Widdel and Wolfe (1989); Bleicher and Winter (1991); Aufhammer et al. (2004); Martin et al. (2020) |
| Bacteria | ||||||
| Fno: F420-reducing NADPH dehydrogenase | Exchanges electrons between NADP and F420. F420 reduction direction dominant in bacteria, as F420 is the secondary cofactor. | Many Actinomycetales (e.g. Streptomyces, Thermobifida, Rhodococcus, Nocardiaand Nocardioides), Chloroflexi?, Alphaproteobacteria?, Betaproteobacteria? | Fno | 1.5.1.40 | 5N2I | Eker, Hessels and Meerwaldt (1989); Heiss et al. (2002); Kumar et al. (2017) |
| Fgd: F420-reducing glucose-6-phosphate dehydrogenase | Heterotrophic growth. Couples oxidation of glucose-6-phosphate to the reduction of F420 via the pentose phosphate pathway. | Many Actinomycetales (e.g. Mycobacterium, Actinoplanes, MicrobacteriumandAmycolatopsis), Chloroflexi, Alphaproteobacteria?, Thaumarchaeota? | LLHT | 1.1.98.2 | 3B4Y | Bashiri et al. (2008); Oyugi et al. (2018) |
| Fsd: F420-reducing sugar-6-phosphate dehydrogenase | Heterotrophic growth. Couples oxidation of glucose-, fructose- or mannose-6-phosphate to the reduction of F420. Similar to Fgd, with a catalytic preference for glucose-6-phosphate, but an expanded substrate specificity. | Some Actinomycetales (e.g. Nocardioides and Cryptosporangium) | LLHT | 1.1.98.2 | Mascotti et al. (2018) | |
| fHMAD: F420-reducing hydroxymycolic acid dehydrogenase | Cell wall biosynthesis. Catalyzes F420-dependent oxidation of hydroxymycolic acids to ketomycolic acids. | Few Mycobacterium (primarily pathogenic species) | LLHT | Bashiri et al. (2012); Purwantini and Mukhopadhyay (2013) | ||
| Amm4: F420-dependent ammosamide dehydrogenase | Putative dehydrogenase involved in primary amide formation in the pyrroloquinoline alkaloid ammosamide. Details of reaction mediated and the product formed are unresolved. | Few Actinomycetales (e.g. Streptomyces and Amycolatopsis) | FDOR-B | Jordan and Moore (2016) |