Table 1. Characteristics of RNA elements that are riboswitch candidates in B. subtilis.

RNA element	Num	Distribution	Term	Reg	Gene functions
glmS	18	B/C, Fus	—	—	GlcN6P synthetase
gcvT	27	B/C, α, β, γ, Act	+	+	Glycine cleavage system, Na+/alanine symporter
ydaO/yuaA	15	B/C, Act	+	—	K+ transporter, membrane metalloproteases
ykkC/yxkD	19	B/C, Cya, α, β, γ, ε	+	+	Multidrug resistance, N/S/B transport
ykoK	21	B/C, β, γ, Act	+	—	Divalent metal transporters
yybP/ykoY	56	B/C, Cya, α, β, γ, Act	+	+	Cation transport ATPase

Motifs are named for the initial gene of each downstream operon in B. subtilis. The number of sequence representatives (Num), evolutionary distribution, presence of an intrinsic terminator before downstream start codons in Gram-positive bacteria (Term), and predicted or known effect of metabolite binding by the RNA element on gene expression (Reg) are shown for each element. Bacterial classification abbreviations: B/C, Bacillus/Clostridium; α, α-proteobacteria; β, β-proteobacteria; γ, γ-proteobacteria; ε, ε-proteobacteria; Cya, cyanobacteria; Fus, fusobacteria; Act, actinobacteria. N/S/B, nitrate/sulfonate/bicarbonate.