Structure of the variable region

HIA-A GSHTVCP GCDNA3SDWBFLPGYHQYAyDGKDYIALKEDLBSWrAAI BA2n HKWEAAHVAEQLRAyi GTCVEMi RYI lJGKErrLCRT 10 20 30 40 50 60 70 80 90 

H-2 KaJ GPHSlPYFVmVSRPG] EPPM EM3YVDDTEFVRFDSDAE pyEPPAP 2E E E TQKAK(3 X E VDl TLI YYW2SKG 

A model has been proposed by which the binding of a peptide to an MHC molecule requires displacement of a structural element spanning a hypervariable region from its normal configuration [109]. Albeit highly speculative, this theory may explain the very slow association rate of the peptide-MHC molecule complex (1 mol/s [120]), since it requires an energetically unfavourable step. 

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Fig. 3.12. Fine structures of the variable regions of antibody light and heavy chains showing the positions of the CDRs. (Adapted from Hood ef al. (1984).)...

Fig. 2.2 Antibodies binding haptens, oligopeptides and oligosaccharides or proteins. Superposed crystal structures of the variable regions were sorted into three classes according to the type of antigen. Structurally variable residues within the CDRs of the antibodies are shown in green those at the N-terminus, to the N-terminal side of CDR-1 and within the outer loop in cyan. Residues within the inner (dimer interface) j8-sheet ofVL...

The overall structure of the variable domain is very similar to that of the constant domain, hut there are nine p strands instead of seven. The two additional p strands are inserted into the loop region that connects p strands C and D (red in Figure 15.8). Functionally, this part of the polypeptide chain is important since it contains the hypervariahle region CDR2. The two extra p strands, called C and C", provide the framework that positions CDR2 close to the other two hypervariahle regions in the domain structure (Figure 15.8). 

Figure 1.10. Generalised structure of the variable and constant domains within antibodies. The variable regions (dark shading) of either the light or heavy chains are indicated as VL or VH, respectively. The light chains also possess one constant region (CL), whereas the heavy chains possess either three or four constant regions (Ch)-Ch4). depending upon the class of immunoglobulin (see text for details).

Mayer et al., 1993). There are interesting similarities between these and the other reported subunit splice variants, indicating some conservation of structure in the variable region. For example, a-subunits and the 82-subunit completely lack variable region sequence, and a 15-AA sequence (-E-P-... -N-K-) at the end of the variable domain in 81 is conserved in the (3- and... 

The basic structure of an Ab molecule is shown in Figure 2. It consists of two identical heavy (H) chains and two identical light (L) chains stabilized and linked by inter- and intrachain disulfide bonds. The H- and L-chains are organized into variable and constant regions. The Ag binding site (combining site) is formed by the association of parts of the variable regions of the H-and L-chains, located at the amino terminal end. The... 

The importance of the immunoglobulins has guaranteed their continued intensive study. The complete sequence of the murine monoclonal immunoglobulin MOPC 173 (IgG 2a, k) has been reported and some genetic implications have been discussed. The a2 heavy chain of a human IgA2 and the k chain produced by mouse MFC II myeloma cells have been completely sequenced and more structures in the variable regions of light and heavy chains reported. ... 

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