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 27886639    24 QTPAYIKVQTNKMVMLSCEAKISLSN--MRIYWLRQrqaPSSDSHHEFLALWDSAKGtihgEEVEQEKIAVFRDASR--F 99
Cdd:pfam07686   1 QTPREVTVALGGSVTLPCTYSSSMSEasTSVYWYRQ---PPGKGPTFLIAYYSNGSE----EGVKKGRFSGRGDPSNgdG 73

                          90       100       110
                  ....*....|....*....|....*....|....*.
gi 27886639   100 ILNLTSVKPEDSGIYFCMIVGSPELTFGKGTQLSVV 135
Cdd:pfam07686  74 SLTIQNLTLSDSGTYTCAVIPSGEGVFGKGTRLTVL 109

Immunoglobulin variable domain (IgV); The members here are composed of the immunoglobulin variable domain (IgV). The IgV family contains the standard Ig superfamily V-set AGFCC'C"/DEB domain topology, and 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. 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" strands in the other.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 27886639  22 LQQTPAYIKVQTNKMVMLSCEAKISLSNMRIYWLRQRQapssDSHHEFLALWDSAKGTIhGEEVEQEKIAVFRDASRFIL 101
Cdd:cd00099   1 VTQSPRSLSVQEGESVTLSCEVSSSFSSTYIYWYRQKP----GQGPEFLIYLSSSKGKT-KGGVPGRFSGSRDGTSSFSL 75

                        90       100       110
                ....*....|....*....|....*....|....*.
gi 27886639 102 NLTSVKPEDSGIYFCMIVGSP---ELTFGKGTQLSV 134
Cdd:cd00099  76 TISNLQPEDSGTYYCAVSESGgtdKLTFGSGTRLTV 111

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 27886639  23 QQTPAYIKVQTNKMVMLSCEAKISLSNMrIYWLRQ--RQAPssdshhEFLAlwdsaKGTIHGEEVEQEKIAVFRDASR-- 98
Cdd:cd04983   2 TQSPQSLSVQEGENVTLNCNYSTSTFYY-LFWYRQypGQGP------QFLI-----YISSDSGNKKKGRFSATLDKSRks 69

                        90       100       110
                ....*....|....*....|....*....|....*....
gi 27886639  99 FILNLTSVKPEDSGIYFCMIVGSP---ELTFGKGTQLSV 134
Cdd:cd04983  70 SSLHISAAQLSDSAVYFCALSESGgtgKLTFGKGTRLTV 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 27886639  22 LQQTPAYIKVQTNKMVMLSCEAK-ISLSNMRIYWLRQR--QAPssdshhEFLALWDSAKGTIHGEEVEQEKIAVFRDA-- 96
Cdd:cd04982   1 LEQPQLSITREESKSVTISCKVSgIDFSTTYIHWYRQKpgQAL------ERLLYVSSTSAVRKDSGKTKNKFEARKDVgk 74

                        90       100       110       120
                ....*....|....*....|....*....|....*....|..
gi 27886639  97 SRFILNLTSVKPEDSGIYFCMIVGSPELT----FGKGTQLSV 134
Cdd:cd04982  75 STSTLTITNLEKEDSATYYCAYWESGSGYyikvFGSGTKLIV 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 27886639     26 PAYIKVQTNKMVMLSCEAKiSLSNMRIYWLRQRQAPSSdshheflalwdsakgtihgeevEQEKIAVFRDASRFILNLTS 105
Cdd:smart00410   1 PPSVTVKEGESVTLSCEAS-GSPPPEVTWYKQGGKLLA----------------------ESGRFSVSRSGSTSTLTISN 57

                           90       100
                   ....*....|....*....|....*....
gi 27886639    106 VKPEDSGIYFCMIVGSPELTFGkGTQLSV 134
Cdd:smart00410  58 VTPEDSGTYTCAATNSSGSASS-GTTLTV 85

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 27886639  37 VMLSCEAK-ISLSNMRIYWLRQrqAPSSDShhEFLALWDSAKGTIHGEEVEQEKIAVFRDASR--FILNLTSVKPEDSGI 113
Cdd:cd04981  16 LKLSCKASgFTFTSYGMGWVRQ--APGKGL--EWIGLIYPGGGDTYYADSFKGRFTITRDTSKstAYLQLNSLTSEDTAV 91

                        90       100
                ....*....|....*....|....*.
gi 27886639 114 YFCMIVGSPELTF-----GKGTQLSV 134
Cdd:cd04981  92 YYCARGLGGYGYSyfdywGQGTTVTV 117

Immunoglobulin (Ig)-like variable (V) domain of Cluster of Differentiation (CD) 8 alpha chain; The members here are composed of the immunoglobulin (Ig)-like variable domain of the Cluster of Differentiation (CD) 8 alpha. The CD8 glycoprotein plays an essential role in the control of T-cell selection, maturation, and the T-cell receptor (TCR)-mediated response to peptide antigen. CD8 is comprised of alpha and beta subunits and is expressed as either an alpha/alpha or alpha/beta dimer. Both dimeric isoforms can serve as a coreceptor for T cell activation and differentiation, however they have distinct physiological roles, different cellular distributions, unique binding partners, etc. Each CD8 subunit is comprised of an extracellular domain containing a V-type Ig-like domain, a single pass transmembrane portion, and a short intracellular domain. The Ig domain of CD8 alpha binds to antibodies. Members of this group contain standard Ig superfamily V-set AGFCC'C"/DEB domain topology.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 27886639  37 VMLSCEAKISLSNmRIYWLRQRQAPSSDSHheFLALWDSAKGTIHGEEVEQEKIAVFRDASRFILNLTSVKPEDSGIYFC 116
Cdd:cd05720  16 VELVCEVLNSVPQ-GCSWLFQPRGSAPQPT--FLLYLSSSNKTKWAEGLDSKRFSGSRSGSSYVLTLKDFRKEDEGYYFC 92

                        90
                ....*....|
gi 27886639 117 MIVGSPELTF 126
Cdd:cd05720  93 SVISNSVLYF 102

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 27886639  24 QTPAYIKVQTNKMVMLSCEAKISlSNMRIYWLRQRQAPSSdshhefLALwdsakgtihgeevEQEKIAVFRDASRFILNL 103
Cdd:cd16096   3 QHPRFAAKKRSSMVKFHCYTNYS-GVMTWFRKKGNQRPQE------LFP-------------EDGRISQTQNGSVYTLTI 62

                        90       100       110
                ....*....|....*....|....*....|....
gi 27886639 104 TSVKPEDSGIYFCMI---VGSPELTFGKGTQLSV 134
Cdd:cd16096  63 QNIQYEDNGIYFCQQkcnSTEPDVTDGCGTELLV 96