Immunoglobulin V-set domain; This domain is found in antibodies as well as neural protein P0 and CTL4 amongst others.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 619634      24 TQDPAVSVALGQTVRITCQ---GDSLRSYYASWYQQKPGQAP--VLVIYGKNNRPSGIPDRFS--GSSSGNTASLTITGA 96
Cdd:pfam07686   1 QTPREVTVALGGSVTLPCTyssSMSEASTSVYWYRQPPGKGPtfLIAYYSNGSEEGVKKGRFSgrGDPSNGDGSLTIQNL 80

                          90       100       110
                  ....*....|....*....|....*....|.
gi 619634      97 QAEDEADYYCNSRDSsgNHVVFGGGTKLTVL 127
Cdd:pfam07686  81 TLSDSGTYTCAVIPS--GEGVFGKGTRLTVL 109

Immunoglobulin (Ig) light chain, kappa type, variable (V) domain; The members here are composed of the immunoglobulin (Ig) light chain, kappa type, variable (V) domain. This group contains the standard Ig superfamily V-set AGFCC'C"/DEB domain topology. The basic structure of Ig molecules is a tetramer of two light chains and two heavy chains linked by disulfide bonds. There are two types of light chains: kappa and lambda, each composed of a constant domain (CL) and a variable domain (VL). There are five types of heavy chains (alpha, gamma, delta, epsilon, and mu), which determines the type of immunoglobulin formed: IgA, IgG, IgD, IgE, and IgM, respectively. In higher vertebrates, there are two types of light chain, designated kappa and lambda, which seem to be functionally identical, and can associate with any of the heavy chains.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 619634    22 ELTQDPA-VSVALGQTVRITCQGD-SLRSYYASWYQQKPGQAPVLVIYGKNNRPSGIPDRFSGSSSGNTASLTITGAQAE 99
Cdd:cd04980   2 VMTQSPAsLSVSPGERVTISCKASqSISSNYLAWYQQKPGQAPKLLIYYASTLHSGVPSRFSGSGSGTDFTLTISSVEPE 81

                        90       100
                ....*....|....*....|....*..
gi 619634   100 DEADYYCNSRDSSgnHVVFGGGTKLTV 126
Cdd:cd04980  82 DAAVYYCQQGYTF--PYTFGGGTKLEI 106

Immunoglobulin (Ig) variable (V) domain of T-cell receptor (TCR) alpha chain and similar proteins; The members here are composed of the immunoglobulin (Ig) variable domain of the alpha chain of alpha/beta T-cell antigen receptors (TCRs). TCRs mediate antigen recognition by T lymphocytes, and are composed of alpha and beta, or gamma and delta polypeptide chains with variable (V) and constant (C) regions. This group represents the variable domain of the alpha chain of TCRs and also includes the variable domain of delta chains of TCRs. Alpha/beta TCRs recognize antigen as peptide fragments presented by major histocompatibility complex (MHC) molecules. The variable domain of TCRs is responsible for antigen recognition, and is located at the N-terminus of the receptor. Gamma/delta TCRs recognize intact protein antigens directly without antigen processing and recognize MHC independently of the bound peptide. Members of this group contain standard Ig superfamily V-set AGFCC'C"/DEB domain topology.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 619634    24 TQDP-AVSVALGQTVRITCQGDSLRSYYASWYQQKPGQAPVLVIYG---KNNRPSGipdRFSGS--SSGNTASLTITGAQ 97
Cdd:cd04983   2 TQSPqSLSVQEGENVTLNCNYSTSTFYYLFWYRQYPGQGPQFLIYIssdSGNKKKG---RFSATldKSRKSSSLHISAAQ 78

                        90       100       110
                ....*....|....*....|....*....|
gi 619634    98 AEDEADYYCNSRDSSGNH-VVFGGGTKLTV 126
Cdd:cd04983  79 LSDSAVYFCALSESGGTGkLTFGKGTRLTV 108

Immunoglobulin (Ig) variable (V) domain of T-cell receptor (TCR) gamma chain; The members here are composed of the immunoglobulin (Ig) variable (V) domain of the gamma chain of gamma/delta T-cell receptors (TCRs). TCRs mediate antigen recognition by T lymphocytes, and are heterodimers consisting of alpha and beta chains or gamma and delta chains. Each chain contains a variable (V) and a constant (C) region. The majority of T cells contain alpha/beta TCRs, but a small subset contain gamma/delta TCRs. Alpha/beta TCRs recognize antigens as peptide fragments presented by major histocompatibility complex (MHC) molecules. Gamma/delta TCRs recognize intact protein antigens directly without antigen processing and recognize MHC independently of the bound peptide. Gamma/delta T cells can also be stimulated by non-peptide antigens such as small phosphate- or amine-containing compounds. The variable domain of gamma/delta TCRs is responsible for antigen recognition and is located at the N-terminus of the receptor. Members of this group contain the standard Ig superfamily V-set AGFCC'C"/DEB domain topology.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 619634    23 LTQ-DPAVSVALGQTVRITCQ--GDSLRSYYASWYQQKPGQAPVLVIY----GKNNRPSGIP-DRFSGS--SSGNTASLT 92
Cdd:cd04982   1 LEQpQLSITREESKSVTISCKvsGIDFSTTYIHWYRQKPGQALERLLYvsstSAVRKDSGKTkNKFEARkdVGKSTSTLT 80

                        90       100       110
                ....*....|....*....|....*....|....*.
gi 619634    93 ITGAQAEDEADYYCNS--RDSSGNHVVFGGGTKLTV 126
Cdd:cd04982  81 ITNLEKEDSATYYCAYweSGSGYYIKVFGSGTKLIV 116

Immunoglobulin like; IG domains that cannot be classified into one of IGv1, IGc1, IGc2, IG.

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 619634       27 PAVSVALGQTVRITCQGDSLRSYYASWYQQKPgqapVLVIYgknnrpsgiPDRFSGSSSGNTASLTITGAQAEDEADYYC 106
Cdd:smart00410   2 PSVTVKEGESVTLSCEASGSPPPEVTWYKQGG----KLLAE---------SGRFSVSRSGSTSTLTISNVTPEDSGTYTC 68

                           90       100
                   ....*....|....*....|
gi 619634      107 NSRDSSGNHVvfgGGTKLTV 126
Cdd:smart00410  69 AATNSSGSAS---SGTTLTV 85

Immunoglobulin (Ig) variable (V) domain of T-cell receptor (TCR) delta chain; The members here are composed of the immunoglobulin (Ig) variable (V) domain of the delta chain of gamma/delta T-cell receptors (TCRs). TCRs mediate antigen recognition by T lymphocytes, and are heterodimers consisting of alpha and beta chains or gamma and delta chains. Each chain contains a variable (V) and a constant (C) region. The majority of T cells contain alpha/beta TCRs, but a small subset contain gamma/delta TCRs. Alpha/beta TCRs recognize antigen as peptide fragments presented by major histocompatibility complex (MHC) molecules. Gamma/delta TCRs recognize intact protein antigens; they recognize protein antigens directly and without antigen processing, and MHC independently of the bound peptide. Gamma/delta T cells can also be stimulated by non-peptide antigens such as small phosphate- or amine-containing compounds. The variable domain of gamma/delta TCRs is responsible for antigen recognition and is located at the N-terminus of the receptor. Members of this group contain standard Ig superfamily V-set AGFCC'C"/DEB domain topology.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 619634    22 ELTQD-PAVSVALGQTVRITCQGD-SLRSYYASWYQQKPGQAPVLVIYGKNNRPSGIPDRFSGS--SSGNTASLTITGAQ 97
Cdd:cd07706   1 KVTQAqPDVSVQVGEEVTLNCRYEtSWTNYYLFWYKQLPSGEMTFLIRQDSSEQNAKSGRYSVNfqKAQKSISLTISALQ 80

                        90       100       110
                ....*....|....*....|....*....|
gi 619634    98 AEDEADYYCNSRDS-SGNHVVFGGGTKLTV 126
Cdd:cd07706  81 LEDSAKYFCALSLPyDTDKLIFGKGTRLTV 110

Immunoglobulin (Ig) heavy chain (H), variable (V) domain; The members here are composed of the immunoglobulin (Ig) heavy chain (H), variable (V) domain. This group contains the standard Ig superfamily V-set AGFCC'C"/DEB domain topology. The basic structure of Ig molecules is a tetramer of two light chains and two heavy chains linked by disulfide bonds. In Ig, each chain is composed of one variable domain (IgV) and one or more constant domains (IgC); these names reflect the fact that the variability in sequences is higher in the variable domain than in the constant domain. There are five types of heavy chains (alpha, gamma, delta, epsilon, and mu), which determines the type of immunoglobulin formed: IgA, IgG, IgD, IgE, and IgM, respectively. In higher vertebrates, there are two types of light chain, designated kappa and lambda, which can associate with any of the heavy chains. This family includes alpha, gamma, delta, epsilon, and mu heavy chains.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 619634    22 ELTQDPAVSVALGQTVRITCQ--GDSLRSYYASWYQQKPGQAP--VLVIY---GKNNRPSGIPDRFSGS--SSGNTASLT 92
Cdd:cd04981   1 QLQESGPGLVKPGQSLKLSCKasGFTFTSYGMGWVRQAPGKGLewIGLIYpggGDTYYADSFKGRFTITrdTSKSTAYLQ 80

                        90       100       110
                ....*....|....*....|....*....|....*..
gi 619634    93 ITGAQAEDEADYYCNSRDSSGNHVVF---GGGTKLTV 126
Cdd:cd04981  81 LNSLTSEDTAVYYCARGLGGYGYSYFdywGQGTTVTV 117

Immunoglobulin variable domain (IgV) Cluster of Differentiation (CD) 79B; The members here are composed of the immunoglobulin variable domain (IgV) of the Cluster of Differentiation (CD) 79B (also known as CD79b molecule, immunoglobulin-associated beta (Ig-beta), and B29). The B lymphocyte antigen receptor is a multimeric complex that includes the antigen-specific component, surface immunoglobulin (Ig). Surface Ig non-covalently associates with two other proteins, Ig-alpha and Ig-beta, which are necessary for expression and function of the B-cell antigen receptor. This gene encodes the Ig-beta protein of the B-cell antigen component. Alternatively spliced transcript variants encoding different isoforms have been described. Members of the IgV family are components of immunoglobulin (Ig) and T cell receptors. The basic structure of Ig molecules is a tetramer of two light chains and two heavy chains linked by disulfide bonds. In Ig, each chain is composed of one variable domain (IgV) and one or more constant domains (IgC); these names reflect the fact that the variability in sequences is higher in the variable domain than in the constant domain. Within the variable domain, there are regions of even more variability called the hypervariable or complementarity-determining regions (CDRs) which are responsible for antigen binding. A predominant feature of most Ig domains is the disulfide bridge connecting 2 beta-sheets with a tryptophan residue packed against the disulfide bond. Members of this group contain standard Ig superfamily V-set AGFCC'C"/DEB domain topology.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 619634    34 GQTVRITCQGDSlrSYYASWYQQKPGQAPVLVIYGKNnrpsgipdRFSGSSSGNTASLTITGAQAEDEADYYCNSRDSSG 113
Cdd:cd16096  13 SSMVKFHCYTNY--SGVMTWFRKKGNQRPQELFPEDG--------RISQTQNGSVYTLTIQNIQYEDNGIYFCQQKCNST 82

                        90
                ....*....|....
gi 619634   114 NHVVFGG-GTKLTV 126
Cdd:cd16096  83 EPDVTDGcGTELLV 96

T-cell receptor Mu, Heavy chain, variable (V) domain; The members here are composed of the immunoglobulin (Ig) heavy chain (H), variable (V) domain of the T-cell receptor Mu. The basic structure of Ig molecules is a tetramer of two light chains and two heavy chains linked by disulfide bonds. In Ig, each chain is composed of one variable domain (IgV) and one or more constant domains (IgC); these names reflect the fact that the variability in sequences is higher in the variable domain than in the constant domain. There are five types of heavy chains (alpha, gamma, delta, epsilon, and mu), which determines the type of immunoglobulin formed: IgA, IgG, IgD, IgE, and IgM, respectively. In higher vertebrates, there are two types of light chain, designated kappa and lambda, which can associate with any of the heavy chains. This family includes alpha, gamma, delta, epsilon, and mu heavy chains. Members of this group contain standard Ig superfamily V-set AGFCC'C"/DEB domain topology.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 619634    34 GQTVRITCQ--GDSLRSYYASWYQQKPGQAPvLVIYGKNNRPSGI-PDRFSGSSSGNTA--SLTITGAQAEDEADYYCNS 108
Cdd:cd16095  15 GKTLSLKCQtsGFQFNTSQLSWYLWVPGHAP-LWLTSLDHISTKVsEDRITSSREDTNSqiFLQIKGLGLRDSGQYHCAR 93

                        90       100
                ....*....|....*....|.
gi 619634   109 RDSSG---NHVVFGGGTKLTV 126
Cdd:cd16095  94 RVGYGddtDKLIFGPGTDVIV 114

Immunoglobulin domain; The members here are composed of the immunoglobulin (Ig) domain found in the Ig superfamily. The Ig superfamily is a heterogenous group of proteins, built on a common fold comprised of a sandwich of two beta sheets. Members of this group are components of immunoglobulin, neuroglia, cell surface glycoproteins, including T-cell receptors, CD2, CD4, CD8, and membrane glycoproteins, including butyrophilin and chondroitin sulfate proteoglycan core protein. A predominant feature of most Ig domains is a disulfide bridge connecting the two beta-sheets with a tryptophan residue packed against the disulfide bond. Ig superfamily (IgSF) domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. Typically, the V-set domains have A, B, E, and D strands in one sheet and A', G, F, C, C' and C" in the other. The structures in C1-set are smaller than those in the V-set; they have one beta sheet that is formed by strands A, B, E, and D and the other by strands G, F, C, and C'. Moreover, a C1-set Ig domain contains a short C' strand (three residues) and lacks A' and C" strand. Unlike other Ig domain sets, C2-set structures do not have a D strand. Like the V-set Ig domains, members of the I-set have a discontinuous A strand, but lack a C" strand.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 619634    37 VRITCQGDSLRSYYASWYqqkpgqapvlviygKNNRPSGIPDRFSGSSSGNTASLTITGAQAEDEADYYC 106
Cdd:cd00096   1 VTLTCSASGNPPPTITWY--------------KNGKPLPPSSRDSRRSELGNGTLTISNVTLEDSGTYTC 56

Immunoglobulin Variable (IgV) domain in HERV-H LTR-associating 2 (HHLA2); The members here are composed of the immunoglobulin variable (IgV) region in HERV-H LTR-associating 2 (HHLA2; also known as B7-H7/B7 homolog 7). HHLA2 is a member of the B7 family of immune regulatory proteins. Mature human HHLA2 consists of an extracellular domain (ECD) with three immunoglobulin-like domains, a transmembrane segment, and a cytoplasmic domain. HHLA2 is widely expressed in human cancers including non-small cell lung carcinoma (NSCLS), triple negative breast cancer (TNBC), and melanoma, but has limited expression on normal tissues. Interestingly, unlike other members of B7 family, HHLA2 is not expressed in mice or rats. HHLA2 functions as a T cell coinhibitory molecules as it inhibits the proliferation of activated CD4(+) and CD8(+) T cells and their cytokine production. Furthermore, HHLA2 is constitutively expressed on the surface of human monocytes and is induced on B cells after stimulation, however it is not inducible on T cells.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 619634    26 DPAVSVALGQTVRITCQGDSLRSYYASWYQQKPGQAPVLVIYGK----------NNRPSGIPDRFSGsssGNtASLTITG 95
Cdd:cd16091   4 EVIVVCLLSEDCILPCSFTPGSEVVIHWYKQDSDIKVHSYYYGKdqlesqdqryRNRTSLFKDQISN---GN-ASLLLRR 79

                        90
                ....*....|....*....
gi 619634    96 AQAEDEADYYCNSRDSSGN 114
Cdd:cd16091  80 VQLQDEGRYKCYTSTIIGN 98