Polypeptide chain conformation

Blake, C.C.F., et al. Structure of human plasma prealbumin at 2.5 A resolution. A preliminary report on the polypeptide chain conformation, quaternary structure and thyroxine binding. J. Mol. Biol. 88 1-12, 1974. 

All transferrins characterized so far consist of a single polypeptide chain of 670-700 amino acid residues. The lactoferrin and serum transferrin structure analyses show that the folding (polypeptide chain conformation) is the same in both proteins and, given their sequence homology, can be assumed to hold for all proteins of the transferrin family. 

In Section II,D,4 we mentioned that recent ab initio calculations of dipole derivatives for the peptide group in NMA have been used to calculate intensities of IR bands in (Gly) I (Cheam and Krimm, 1985). Such calculated intensities are shown in Fig. 7, and it can be seen that they reproduce the observed intensities quite well. This kind of agreement indicates that the force field is a very satisfactory one, since intensities are a sensitive function of the eigenvectors. While (Gly) I is the only polypeptide so far for which intensities have been calculated, it can be expected that this technique will be used in the future to provide additional information on polypeptide chain conformation. 

It is clear that vibrational analyses of helical polypeptide chain conformations are of major importance to the study of protein structure, and the initial efforts made in this direction are discussed in the remainder of this section. 

A comparison of CD spectra (200—600 nm) between bovine heart fenicytochrome c and ferricytochrome from Rhodospirillum rubrum showed marked differences, while the spectra were more similar in the reduced forms. These differences were attributed to subtle variations around the hemes rather than to differences in the polypeptide chain conformations (216). Optical activity studies of cytochromes C3 showed similarities among three species of Desulfovibrio but revealed differences from mammalian cytochrome c. Rotatory strengths of the resolved CD... 

Ramachandran GN, Ramakrishnan C, Sasisekharan V. Stereochemistry of polypeptide chain conformations. J Mol Biol 1963 7 95-99. 

D, C. Rappaport and H. Scheraga, Macromolecules, 14, 1238 (1981).Evolution and Stability of Polypeptide Chain Conformation A Simulation Study. 

HiPIP from Chromatium vinosum contains three tryptophan residues (W60, W76 and W80) (Fig. 7.5). The distance between tryptophan 80 and the Fe4S4 cluster (7.5 A) and their relative orientation contribute to a high energy transfer FOrster type. Fe-S bonds covalently bind the Fe4S4 cluster to the protein matrix at cysteine residues 43.46, 63 and 77. The polypeptide chain conformation may be described as a sequence of a helical or extended conformations and hairpin turns (Carter et a. 1974). 

Baker, E.N. 1977. Structure of actinidin Details of the polypeptide chain conformation and active site from an electron density map at 2.8 A resolution. J. Mol. Biol 115, 263-277. 

Stereochemically acceptable extended-chain (so-called yS-sheet) structures were first described by Pauling and Corey from molecular model building [78, 79]. In some cases, specific structures of synthetic polypeptides have been deteraiined from X-ray diffraction studies. These have provided the bases for the vibrational analyses of this class of polypeptide chain conformations. 

Fig. 2.16. Polypeptide chain conformation in the chymotrypsin molecule (according to Lehninger, 1977)...

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