Table 3.

Most Versatile Superfamily Combinations in Multi-Domain Proteins

No.func No.prot Sfam comb. Function SWISS-PROT ID SWISS-PROT function
29#THB_RANCAThyroid Hormone Receptor Beta
10#HNF4_DROMETranscription Factor HNF-4 Homolog
31#32#EAR2_MOUSEV-Erba Related Protein Ear-2
29#30#ECR_MANSEEcdysone Receptor (Ecdysteroid Receptor)
221761.95.1/7.33.132#ERBA_AVIERErba Oncogene Protein
556#564#35#NGFI_XENLANerve Growth Factor Induced Protein I-B
576#NR42_HUMANImmediate-Early Response Protein Not
36#PPAT_HUMANPeroxisome Proliferator Activated Receptor
37#RXTG_CHICKRetinoic Acid Receptor RXR-Gamma
38#TLL_DROVITailless Protein
E1.8.2DHSU_CHRVISulfide Dehydrogenase (1.8.2.–)
E1.8.1DLDH_ZYMMODihydrolipoamide Dehydrogenase (1.8.1.4)
 8 543.4.1/4.48.1E1.6.4TYTR_TRYCRTrypanothione Reductase (1.6.4.8) (Tr)
E1.16.1MERA_STRLIMercuric Reductase (1.16.1.1)
E1.6.99NAOX_MYCPNProbable NADH Oxidase (1.6.99.3) (Noxase)
19#ARYB_MANSEArylphorin Beta Subunit–(Tobacco Hornworm)
20#CRPI_PERAMAllergen Cr-Pi Precursor–(American Cockroach)
21#427#HCY_PALVUHemocyanin–(European Spiny Lobster)
 8 231.78.1/2.1.122#HEXA_BLADIHexamerin Precursor–(Tropical Cockroach)
23#JSP1_TRINIAcidic Juvenile Hormonne–Suppressible Protein
24#LSP2_DROMELarval Serum Protein 2 Precursor (LSP-2)
546#25#SSP1_BOMMOSex-Specific Storage–Protein 1

[i] Note that the combination with the greatest number of different functions is that of 1.95.1 and 7.33.1. Careful examination reveals that all the proteins with this combination are DNA-binding and most of them act as various hormone receptors. In particular, HNF4_DROME and NR42_HUMAN also have transcription activator functions. Note that these two proteins are considerably longer than the others in this group and are not covered completely by structural matches: A large C-terminal and a large N-terminal portion are left uncovered, respectively.