TABLE 2.

Identification of genes encoding subunits for T. cruzi complex II

Subunita	Sequence confirmedb	Accession number or RefSeq ID at NCBI (haplotype,cMr)	Identityd	TMe
			%
SDH1	Ser10-Met19	AB031741 (NE, 66,974), XP_809281 (E, 18,231)	59	0
SDH5	Ala10-Leu19	XP_818124 (NE, 53,831), XP_810172 (E, 20,788)	16	0
SDH2N	Ser188-Arg196, Lys201-Ile204, Gly221-Asn223, Glu267-Ile269	XP_814994 (merged, 32,232)f	24 (37)	0
SDH2C	Pro2-Leu6	XP_803796 (NE, 21,352), XP_806126 (E, 21,379)	25 (43)	0
SDH6a	Val19-Val28	XP_809065 (NA, 36,077), XP_812789 (NA, 36,035)	15	0
SDH6b	Val19-Val28	XP_813603 (NA, 36,133), XP_813645 (NA, 36,039)	14	0
SDH7	Ile26-Leu35	XP_813318 (NE, 28,218), XP_820239 (E, 28,202)	22	0
SDH3	Val2-Phe11	XP_809410 (NE, 12,176), XP_810064 (E, 12,204)	29	1
SDH4	Phe39-Thr48	XP_808211 (E, 13,957), XP_816430 (NE, 13,975)	27	2
SDH8	Gly5-Met16	XP_809192 (NE, 16,199), XP_817545 (E, 16,143)	NDg	2
SDH9	Ile10-Pro19	XP_807105 (merged, 15,736)	ND	1
SDH10	Pro25-Val33	XP_808894 (NE, 15,565), XP_808903 (E, 15,554)	ND	1
SDH11	Phe20-Cys29	XP_814088 (E, 10,346), XP_814509 (NE, 10,337)	ND	1

^aAlleles were named as SDH3-1 (XP_809410) and SDH3-2 (XP_810064) in the order of the accession numbers, except for SDH5.

^bThese are N-terminal sequences except for SDH2_N and SDH8, where the N-terminal residues were blocked.

^cHomozygous alleles located in a merged assembly of Esmeraldo (E) and non-Esmeraldo (NE) homologous sequences whose different copies were merged genes during the genome assembly are indicated by “merged.” Haplotypes for gene with more than two copies in the genome that does not belong to a merged region are not assigned (NA).

^dIdentity % to counterparts in human were as follows: SDH1 (D30648), SDH2 (P21912), SDH3 (Q99643), or SDH4 (O14521). In parentheses, the identity % of SDH2_N and SDH2_C that correspond to either Met¹-Pro¹⁵⁵ (Ip_N domain) or Tyr¹⁵⁶-Val²⁸⁰ (Ip_C domain), respectively, of human SDH2 is shown. Identity % for truncated forms of SDH1 and SDH5 (SDH1-2 and SDH5-2) in the Esmeraldo haplotype was 66 and 20%, respectively.

^eTransmembrane segments (TM) were estimated with TMHMM (52) and SOSUI (53).

^fSDH2N from other trypanosomatids lack Met¹ to Arg⁴² of TcSDH2_N.

^gND indicates not determined because these hydrophobic sequences are a highly divergent form of mammalian sequences.