Table 1.

SFLD Subgroups, Names, and (Mega)Clusters in RadicalSAM.org

Subgroup	Subgroup Name	RS.org (Mega)cluster
1	7-carboxy-7-deazaguanine synthase-like	Megacluster-3-1
2	Coproporphyrinogen III oxidase-like	Megacluster-2-2
3	Antiviral proteins (viperin)	Megacluster-1-5
4	Avilamycin synthase	Megacluster-1
5	B12-binding domain containing	Megacluster-2-1
6	Biotin and thiazole synthase domain containing	Megacluster-4
7	DesII-like	Megacluster-1-8
8	ELP3/YhcC	Megacluster-2-4, -2-5
9	F420, menaquinone cofactor biosynthesis	Megacluster-4-2
10	FeMo-cofactor biosynthesis protein	Megacluster-1-4
11	Lipoyl synthase like	Cluster-8
12	Methylthiotransferase	Megacluster-2-3
13	Methyltransferase Class A	Cluster-6
14	Methyltransferase Class D	Megacluster-1-3
15	Organic radical activating enzymes	Megacluster-3
16	PLP-dependent	Megacluster-7
17	SPASM/twitch domain containing	Megacluster-1-1
18	Spectinomycin biosynthesis	Megacluster-1-1
19	Spore photoproduct lyase	Megacluster-5-3
20	tRNA wybutosine-synthesizing	Cluster-10
	Protein MJ0683-like	Megacluster-5-1
	Uncharacterized protein family UPF0313	Cluster-10
	DUF5131	Megacluster-5-2
	3’,8-Cyclase/Mo cofactor synthesis	Megacluster-1-2