Polypeptide chains structure

The term primary structure is used to describe the sequence of amino acid units (configuration) in a polypeptide chain. Structure 10.5 is an example of a primary structure. 

Figure 3.8. Basic Four—polypeptide chain structural unit of an immunoglobulin. <- - represents the antibody-combining sites.(From Butler 1969. Reprinted with permission of the American Dairy Science Association.)...

Melcher, U. Uhr, J.W. (1976). Cell surface immunoglobulin. XVI. Polypeptide chain structure of mouse IgM and IgD-like molecule. J. Immunol. 116,409-415. 

Pauling, L., and Corey, R. B. (1953). Compound helical configurations of polypeptide chains Structure of proteins of the a-keratin type. Nature 171, 59-61. 

Figure 2.7. Polypeptide chain structure containing proline. Chains containing proline lack the flexibility of other peptides because the proline ring has only one available angle for backbone rotation. Rotation occurs around the angles ( ), /, and co.

FIGURE 2 Pentameric polypeptide chain structure of human IgM. The IgM heavy chain have five domains with disulfide bonds crosslinking adjacent C/j.3 and C/j.4 domains of different units. Also shown are the carbohydrate side chains and possible location of the J chain. (Reprinted from Roitt et o/.")... 

In a subsequent paper Brant and Flory (55) have successfully correlated their experimental data with polypeptide chain structure using the rotational-isomeric state model and statistical mechanical methods applicable to linear systems of interacting subunits. 

The eigenvectors of polypeptide chain modes, as in the case of NMA, can be described by PEDs in terms of symmetry coordinates, which in turn are related to internal coordinates. A list of the internal coordinates for (Ala) is given in Table IV, and the local symmetry coordinates are given in Table V (Moore and Krimm, 1976b). These serve as the general local symmetry coordinates for most polypeptide chain structures [for the particular set for (Gly) I, see Dwivedi and Krimm (1982a)]. 

The goal of a vibrational spectroscopic study of a polypeptide molecule is to derive structural information from spectral parameters, such as band frequencies, intensities, and polarizations. In the past, the frequencies of the amide modes were the main diagnostic quantities, with structural insights being obtained from correlational studies based on observed spectra of known polypeptide chain structures. 

We have noted the importance of incorporating calculations of IR intensities in the analysis of spectra. This approach is certain to prove fruitful in a number of areas determination of the dependence of amide mode intensities on conformation influence of size and perfection of structure on intensities correlation of intensities with hydrogen-bond geometry (Cheam and Krimm, 1986). Just as it is possible to develop a conformational (, i/ )-frequency map (Hsu et al., 1976), it should be possible to compute a conformational (, i/ )-intensity map, which could be useful in analyzing the spectra of unordered polypeptide chain structures. Of course, nothing has yet been done on the calculation of Raman intensities of polypeptides, and this area is ripe for future development. 

Much remains to be done in characterizing the vibrational spectra of known polypeptide chain structures. Although some preliminary studies were done on the parallel-chain pleated sheet (Krimm and Abe, 1972 Moore and Krimm, 1975), a full analysis of this structure found in... 

E. G. Petrov, Role of Polypeptide Chain Structure in Donor-Acceptor Electron Transfer through Proteins, Studia Biophysica 93, 237-240 (1983). 

Compound Helical Configurations of Polypeptide Chains Structure of Proteins of the a-Keratin Type... 

HELICAL CONFIGURATIONS OF POLYPEPTIDE CHAINS STRUCTURE OF PROTEINS OF THE a-KERATIN TYPE ... 

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