Antibodies Light chain

Boc-E4 Boc-EAR lR-MCA BJP-B6 + MCA Autoantibodies Bence Jones proteins (BJPs) (monoclonal antibody light chains) isolated from the urine of multiple myeloma patients, were found to hydrolyse peptide methylcoumarin amide peptide-MCA substrates 1.5 x 101 3.3 X 1()-2 nr 5.8... 

Figure 11.6. Schematic diagram showing the assembly of IL-12 protein for antibody-based drug delivery, (a) The mature sequences of the p35 subunit of IL-12 are fused to the C-terminus of the heavy chain of a tumour-specific antibody and co-expressed with the antibody light chain and the p40 subunit of IL-12. Formation of the final immunocytokine requires the creation of disulfide bridges between the antibody chains and interactions of p35 and p40 subunits of IL-12 [119]. (b) Alternatively the IgG heavy chain and both subunits of IL-12 can be linked via flexible linkers allowing for equimolar assembly of IL-12 [120].

TEL His-121 makes only one hydrogen bond to the antibody light chain and induces a peptide flip between residues VlW92 and VlS93, a conformational change that is likely responsible for the slower on-rate of the interaction (Fig. 1C). 

Fig. 13.3. The assembly of an antibody light chain. V Vj..V are variable domains, Ji, J2, Jj and J4 are joining domains and C...

The carboxyterminus forms the flap, a series of three concatenated Ig-like domains. The first two domains resemble the V and C regions of an antibody light chain the most carboxyterminal such domain is a truncated V domain. The... 

The most remarkable feature of the antibody molecule is revealed by comparing the amino acid sequences from many different immunoglobulin IgG molecules. This comparison shows that between different IgGs the amino-terminal domain of each polypeptide chain is highly variable, whereas the remaining domains have constant sequences. A light chain is thus built up from one amino-terminal variable domain (Vl) and one carboxy-terminal constant domain (Cl), and a heavy chain from one amino-terminal variable domain (Vh), followed by three constant domains (Chi, Ch2. and Chs). 

IgG antibody molecules are composed of two light chains and two heavy chains joined together by disulfide bonds. Each light chain has one variable domain and one constant domain, while each heavy chain has one variable and three constant domains. All of the domains have a similar three-dimensional structure known as the immunoglobulin fold. The Fc stem of the molecule is formed by constant domains from each of the heavy chains, while two Fab arms are formed by constant and variable domains from both heavy and light chains. The hinge region between the stem and the arms is flexible and allows the arms to move relative to each other and to the stem. 

Figure 17.2 An example of prediction of the conformations of three CDR regions of a monoclonal antibody (top row) compared with the unrefined x-ray structure (bottom row). LI and L2 are CDR regions of the light chain, and HI is from the heavy chain. The amino acid sequences of the loop regions were modeled by comparison with the sequences of loop regions selected from a database of known antibody structures. The three-dimensional structure of two of the loop regions, LI and L2, were in good agreement with the preliminary x-ray structure, whereas HI was not. However, during later refinement of the x-ray structure errors were found in the conformations of HI, and in the refined x-ray structure this loop was found to agree with the predicted conformations. In fact, all six loop conformations were correctly predicted in this case. (From C. Chothia et al.. Science 233 755-758, 1986.)...

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