Table 1.

F₄₂₀-dependent enzyme families.

F420-dependent protein family	Acronym	Protein fold	Mechanism of hydride transfer	Phylogenetic distribution	Characterized function(s)	Key references
Flavin/deazaflavin oxidoreductase	FDOR-A, FDOR-B	Split β-barrel	Direct F420-substrate	Actinobacteria, Chloroflexi	F420H2-dependent reduction of diverse substrates (e.g. menaquinone, tetracycline and biliverdin) with promiscuous activity often observed	Cellitti et al. (2012); Lapalikar et al. (2012); Ahmed et al. (2015); Greening et al. (2017)
Luciferase-like hydride transferase	LLHT	TIM-Barrel	Direct F420-substrate	Broadly found in F420 producing bacteria and archaea	F420-dependent oxidation or F420H2-dependent reduction of diverse substrates (e.g. G6P, mycolic acids and CH2=H4MPT)	Aufhammer et al.(2004, 2005); Bashiri et al. (2008); Nguyen et al. (2017); Mascotti et al. (2018)
F420-dependent NADPH oxidoreductase	Fno	Rossmann fold	Direct F420-substrate	Broadly found in F420 producing bacteria and archaea	Hydride transfer between F420/F420H2 and NADP/NADPH	Berk and Thauer (1997); Warkentin et al. (2001); Le et al. (2015); Joseph et al. (2016); Kumar et al. (2017)
F420-dependent H4MPT oxidoreductase	Mtd	Rossmann fold	Direct F420-substrate	Euryarchaeota: methanogens, ANME, Archaeoglobales	Hydride transfer between F420/F420H2 and CH≡H4MPT/CH2=H4MPT	Shima et al. (2000); Hagemeier et al. (2003a); Warkentin et al. (2005); Ceh et al. (2009)
F420H2-dependent flavodiiron oxidase	FprA	β-lactamase/flavodoxin	Indirect F420-flavin-2Fe-O2	Methanogenic archaea	Reduction of dioxygen (O2) to water (2 H2O) to detoxify O2	Seedorf et al. (2004,2007)
F420-dependent redox coupling oxidoreductase	FDRC	α/β/α-sandwich fold	Indirect F420-flavin-FeS-substrate	Euryarchaeota: methanogens, ANME, Archaeoglobales	Couples the reduction/oxidation of F420/F420H2 to that of formate, H2, methanophenazine, quinone or sulfite, via association with structurally diverse protein subunits.	Baron and Ferry (1989); Bäumer et al. (2000); Brüggemann, Falinski and Deppenmeier (2000); Johnson and Mukhopadhyay (2005,2008b); Welte and Deppenmeier (2011a); Allegretti et al. (2014); Vitt et al. (2014)
Deazaflavin-dependent thioredoxin reductase	DFTR	Thioredoxin reductase fold	Indirect F420-flavin-disulfide	Euryarchaeota: Methanococcales	Couples F420H2 oxidation to the reduction of thioredoxin	Susanti, Loganathan and Mukhopadhyay (2016)
F420-dependent bifurcating reductase	HdrA2	HdrA-like fold	Indirect F420-flavin-FeS-substrate	Euryarchaeota: Methanosarcinales	Couples F420H2 oxidation to the reduction of CoM-S-S-CoB and ferredoxin via bifurcation	Yan, Wang and Ferry (2017)