Here you are: IMGT Web resources > IMGT Repertoire (RPI) > 2. Proteins and alleles
Citing this figure: Bernard D., Hansen J.D., Du Pasquier L., Lefranc M.-P., Benmansour A. and Boudinot P. "Costimulatory receptors in non mammalian vertebrates: conserved CD28, odd CTLA4 and multiple BTLAs" Dev. Comp. Immunol. 31, 255-271 (2007) PMID: 16928399 [1]

   
             <——————————— L-REGION ——————————> <————————————— C-LIKE-DOMAIN ————————————
                                                      A        AB     B          BC        
                                                   (1-15)          (16-26)    (27-38)    
                                              ———————————————>   ——————————>               
                                              1         10  15   16  20 2326 27      36  
                                      87654321 | ........|....|123|...|..|..| |........|  
   Danrer     MSFFFQIFCNVAVSLLLLSLSVSGTSNGTEPH CDVKLKVPRQTIFKARI..MTQLKINCTVT HNG....CQW
   Oncmyk1                      ~LCVHGNAQDQGPT CEV..RVKRNTIWNAVP..QKALTINCPVR HCG.....EK
   Oncmyk2        MDPLWSDHILLVLCLLFLVCINGNAQGP CEIEVPIKRNTVWNAVP..QKRLTINCPVK HCG.....ET
   XenTro            MRGRGNFLNSLNVGCVRAQGRCKSE CSPQIHTERNTKYNESV..GESLAIQCPVS FCSK....EL
   Homsap   MLGTGKLFWVFFLIPYLDIWNI.......HGKES CDVQLYIKRQSEHSILA..GDPFELECPVK YCA.....NR
   Musmus   MLGTPRLFREFF.ILHLGLWSILCEKATKRNDEE CEVQLNIKRNSKHSAWT..GELFKIECPVK YCV.....HR

   
                —————————————————————— C-LIKE-DOMAIN —————————————————————
                   C           CD          D           DE          E                    
                (39-45)                 (77-84)                 (85-96)              
                ——————>                 ———————>              ———————————>                         
                3941 45                 77 80 84              85  89    96  
                |.|...| ABC DEF 1234567 |..|...|12345677654321|...|......|12
   Danrer       NPISWCK IYG DHC KALNHSD LIKMECRNTAQ.........HEGMAFLIFQNITM
   Oncmyk1      LHATWCK FVDLLNC EQIHETE QVTFGWRQK.............DILILDFKKISI
   Oncmyk2      LRVTWCK FED ANC KQINETE QVKIGWKPFDRG.......SENRIAFLDFKKISR
   Xentro       PVVSWCK FVG ETC ESLSAGP GRLMEWTDRK.........ENTAVYLLTFVGAQL
   Homsap       PHVTWCK LNG TTC VKLE... DRQTSWKEEK..........NISFFILHFEPVLP
   Musmus       PNVTWCK HNG TIW VPLEVGP QLYTSWEENR..........SVPVFVLHFKPIHL

   
                ————————— C-LIKE-DOMAIN —————————> <——————— CONNECTING-REGION —————————>

                   F           FG           G             
                (97-104)    (105-117)   (118-128)               
                ———————>               ——————————>
                97   104  105  111 117 118     128
                |......| |.....|.....| |.........|
   Danrer       ENSGSYRC THG......DTSV SHAINVTITGN .......GEDEFSHNQSNKTDDFNSVPDNGLK 
   Oncmyk1      NDDGLYRC GVAEN...GSTTV SHAIKVSVSDS .......NLEITSTADHNTNDSTDAKRDRNDPS
   Oncmyk2      NDDGSYRC GMAGK...KSSIV SHAINVSVSDI .......NLTMTSTADHNTNNSPNAKHDEKYLS
   Salsal                                  ~VSVSDR .......NLKMTSTAEHNTNDSTIKKHDEKYLS
   Xentro       NDTGYYRC TLTTQ...SVNTV GRTVMVKIIGH .......KERTTAQLPSTTHIMGGCSRVEGSTQPGY
   Homsap       NDNGSYRC SANFQ...SNLIE SHSTTLYVTDV ...........KSA......SERPSKDEMASRP
   Musmus       SDNGSYSC STNFN...SQVIN SHSVTIHVRER TQNSSEHPLITVSDIPDATNASGPSTMEERPGRT
   
   
                 <—————————— TM ———————————> <———————————————————— IC —————————————————————
   Danrer        WLWPYVYICSGIAALVIIIITITLFVF NCQDTKSKTEELTNKNQYMETQSSDLLPPPLPHPRHDTR......
   Oncmyk1       FM.PYVYICVGIAVLVVIVTAFSFFCL HAYKGPSRSTGNRTKKQEMSTLTAPCPDLSFNPEETFPSSPSTPN
   Oncmyk2       WL.PYAYICVGIVLLVVVVTPISFFYL YGCKGPTRSTNNGIKEQ.....AAPCPDLSSCSKG/
   Salsal        WL.PYVYICVGIVLLVVVVTAISFLCI YGCKGPTRSTNNGIMEQ.....AAPCPDLSSCSKGTFPSSPSTPN
   Xentro        WV.ILLRILIVIGASSLLFYCLGTITA NRRFSKTLRRENVTGINA....SKTPISAVEPLDIGSLHTPGP 
   Homsap        WL.LYSLLPLGGLPLLITTCFCLFCCL RRHQGKQNELSDTAGRE..INLVDAHLKSEQTEASTRQNS...QV
   Musmus        WL.LYTLLPLGAL.LLLLACVCLLCFL KRIQGKEKKPSDLAGRD..TNLVDIP.......ASSRTNH...QA
   
   
                 ———————————————————————————————————— IC ——————————————————————————————————
   Danrer        SLSQQRGSALDRGSEIPPGRGTSSAGRVKERSHHTVSAGRGEDDNALVYASLNHQAVPKVHRKTARQEPELS
   Oncmyk1       PVQPANLYDNGLYCNRINGKNGALPFS/
   Salsal        PAHSDNLYNNGPYGKHINRASAHSLLVTNGTLPSSDITARGQGSNHLVYASLNHQTPRESLKPPHIPNPQDECS
   Xentro        ASANEITYNNITAEETCSSVEDSNDKEQNQTA*
   Homsap        LLSETGIYDNDP..........DLCFRMQEGSEVYSNPCLEENKPGIVYASLNHSVIGLNSRLARNVKEAPT
   Musmus        LPSGTGIYDNDP............WSSMQDESELTISLQSERNNQGIVYASLNHCVIGRNPRQENNMQEAPT
   
   
                 ————————>
   Danrer        EYAAVRFR*
   Salsal        EYAAIRVY*
   Homsap        EYASICVRS*
   Musmus        EYASICVRS*

Legend:
References:
[1] Bernard D. et al., Dev. Comp. Immunol. 31, 255-271 (2007). PMID: 16928399
[2] Lefranc M.-P. et al., Dev. Comp. Immunol., 29, 185-203 (2005) PMID: 15572068 pdf with permission from Elsevier
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