Table 2.

Eukaryotic SC proteins, their functional domains, and the total protein size (amino acid residues, aa).

SC central space proteins			LE proteins and other SC proteins
Protein	Functional domainsa	Total size, aa	Protein	Functional domainsa	Total size, aa
Zip1 Scb	Bacterial SMC, Smc, AAA_13	875	Hop1 Sc	HORMA	605
ZYP1a At	Two bacterial SMC domains	871	Red1 Sc	Rec10/Red1	827
ZYP1b At	Two bacterial SMC domains, PRK00409	856	Hop1 Sp, a linear element component	RING finger	528
C(3)G Dm	Two bacterial SMC domains	744	Rec10 Sp, a linear element component	Rec10/Red1	791
CORONA Dm	—	207	ASY1 At	HORMA, SWIRM	596
SYP-1 Ce	Smc	489	ASY2 At	HORMA	1399
SYP-2 Ce	—	213	C(2)M Dm	Rad21_Rec8_N cohesin domain	570
SYP-3 Ce	SGNH_plant_lipase_like	224	HIM-3 Ce	HORMA	291
SYP-4 Ce	—	605	SYCP2 Dr	—	995
SYCP1 Dr	SCP-1	537	SYCP3-like Dr	COR1	240
SYCE1-like Dr	—	206	SC65 Dr, a SC protein	Bacterial rpoC2_cyan	426
SYCE2 Dr	—	187	SYCP2 Mm	Bacterial COG4399	1500
TEX12 Af	—	135	SYCP3 Mm	COR1	254
SYCP1 Mm	SCP-1	993	SC65 Mm, a SC protein	—	443
SYCE1 Mm	Bacterial SMC	329	FKBP6 Mm, peptidyl-prolyl cis-trans isomerase	FKBP_C, TPR	327
SYCE2 Mm	—	177
SYCE3 Mm	—	88
TEX12 Mm	—	123

^aAccording to the CDART output.

^bThe model organisms are designated as in Table 1. See protein IDs in Table 1.

The SMC, Smc, SCP-1, COR1, and RAD21 domains are characteristic of structural chromosome proteins. The HORMA domain recognizes the chromatin state and facilitates the interactions with other proteins. PRK00409 is involved in recombination. Cis-trans isomerases catalyze the isomerization of protein molecules having double bonds. The other domains are not related to meiosis.