Table 2.

Comparison of DNA-recognition helices and linkers in TFIIIA sequences

TFIIIA sequence	Amino acid alignment
Helix residues −1, +2, +3, and +6 in fingers: 1, 2, 3, and 5*
Xenopus laevis	KWKA	SHHR	TANK	LSRR
Xenopus borealis	KWKA	SHHR	TANK	VSCR
Rana pipiens	KWKA	TFHR	TTNK	SSRR
Rana catesbeiana	KWKA	TFHR	TTNK	SSRR
Bufo americanus	KRKA	THHR	TSNL	SSRR
Homo sapiens	KWKA	RYHR	TSNK	SSKR
Ictalurus punctatus	KWKA	TCQR	SAGN	TKKK
Saccharomyces cerevisiae	RISE	KSHR	TQRR	RYRN
Linker sequences: 1–2, 2–3, 3–4, 4–5, and 5–6†

Xenopus laevis	TGEKP	TGEKN	NIKICV	TQQLP	AG
Xenopus borealis	TGEKP	TGEKN	NLQLCV	TQQLO	AG
Rana pipiens	TGERP	TGEKP	LSPSLI	TNQQP	AG
Rana catesbeiana	TGERP	TGEKP	LSPSLI	TNQQP	AG
Bufo americanus	TGERP	TGEKP	SSPAQI	TNQQP	AG
Homo sapiens	TGERP	TGEKP	QNQQKQ	TNEPL	EG
Ictalurus punctatus	TGLRP	SGKKP	QHKEKH	MNQLP	DV
Saccharomyces cerevisiae	QGLRA	SDTKP	TKS	LHK	HDPEVENP

^*Amino acids occurring at helix positions −1, +2, +3, and +6 (42–48) that contact DNA bases and share sequence identity with X. laevis are shown in bold. 

^†Residues in linkers that are identical to the X. laevis sequence are also shown in bold.