TABLE 3.

Classification of SURP1 domains in humans

Connection between α1 and α2	Classification	SURP‐containing protein	SURP domain	Type‐specific residues	A binding protein
G‐bend	Type 1a a	SF3A1	SURP1
		SFSWAP	SURP2	R62, N63, K80 b	SF1
		CHERP	SURP
	Type 1b	SFSWAP	SURP1	– c	–
		SR140	SURP	–	–
		SF4	SURP1	–	–
		SF4	SURP2	–	–
		SFRS14	SURP2	–	–
	Type 2	SF3A1	SURP2	F162, L169	SF3A3
Loop	Type 3	SFRS14	SURP1	–	–

^a Currently, Type‐1 SURP domains are divided into two subtypes, depending on whether they can bind to SF1.

^b The residue number is according to SF3A1 SURP1.

^c “–” refers to “unknown.”