Chain pair

Figure 20.11 Papain digestion of IgG antibodies primarily results in cleavage in the hinge region above the interchain disulfides. This produces two heavy-light chain pairs, called Fab fragments, each containing one antigen binding site. The Fc region normally can be recovered intact.

Chain Pair Modeling. In the following analysis, we assume that the chains are regular helices, i.e. that they have screw symmetry, with a repeat distance, t. In a perfect crystal, such chains must either be parallel or antiparallel. Four interhelical parameters are required to define the geometric orientation of chain A relative to chain B (see Figure 2). The parameters and their ranges are ... 

Table 2 Description of the Geometrical and Energetical Features of the Significant Low-Energy Chain-Pairings...

De Wildt, R.M.T., Hoet, R.M.A., van venrooij, W.J., Tomlinson, I.M., Winter, G.. (1999a). Analysis of heavy and light chain pairings indicates that receptor editing shapes the human antibody repertoire. J. Mol. Biol., 285, 895-901. 

Fraction of chain pairs belonging to topological class i. 

Thus the amino acid analysis, when taken in conjunction with the sedimentation properties of these components, suggests that the a-component is a mixture of two polypeptide chains of about the same mass but differing composition, while the /3-component consists of a mixture of two different types of cross-linked chain pairs, i.e., al-al and al-a2. 

A very interesting aspect of the reversion to collagen has arisen from the studies of Grassmann et al. (1960). They digested denatured acid-soluble collagen with trypsin and found that a number of the peptides had a three-chain structure. The denatured material must consist of single chains and chain pairs (see Section II,C) with very few triple-chain molecules. This state of affairs presumably persisted during proteolysis, and therefore the resultant peptides must then take on a heli( al form and associate to form triple-chain molecules. This demonstrates the favorableness of the three-chain structure for imino acid-rich peptides. 

Octahedral structures (see Chapter 5) include two closely related chain structures, a-Nbl4 and TcCl4 and the layer structure of Snp4 (and the isostructural NbF4( and PbF4). In the a-Nbl4 chain pairs of Nb atoms are alternately closer together and further apart (Fig. 9.10(a)), and the interaction... 

Studied the effects of bond and atom alternations and of chain pairing on the NLO properties of one-dimensional periodic semiconductors, with special emphasis on polydiacetylenes (PDA). The properties were referred to as and but we prefer and this is more correct to write 3(A)/A and y(N)/N with N, the number of units, tending toward infinity. Another Hiickel investigation [174] concentrated on (a) the second-order NLO responses of asymmetric unit cell polymers that modeled polymethineimine (PMI) and (b) the relations between bond alternation, atom alternation, and the sign and magnitude of p(/V)//V. At this level of theory the equations reduced to the non-self-consistent scheme detailed above and can be called uncoupled. 

The normal base pairs in DNA. Adenine in one polynucleotide chain pairs with thymine in the complementary chain guanine pairs with cytosine. A-T base pairs are joined by two hydrogen bonds G-C base pairs are Joined by three hydrogen bonds. 

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