Poly conformational studies

VNR Pillai, M Mutter. Conformational studies of poly(oxyethylene)-bound peptides and protein sequences. Acc Chem Res 14, 122-130, 1981. 

N. K. Kochetkov, O. S. Chizhov, and A. S. Shashkov, Dependence of 13C chemical shifts on the spatial interaction of protons, and its application in structural and conformational studies of oligo- and poly-saccharides, Carbohydr. Res., 133 (1984) 173-185. 

The effect of the side chain structure on the solution behavior as well as in the solid state of vinyl polymers has been studied in the past for a number of poly(methacrylate)s [72,73,76], The conformational study of polymers containing... 

Gerald D. Fasman, Poly-a-Amino Acids, Protein Models for Conformational Studies, in Biological Macromolecules, Vol. 1, Dekker, New York, 1967. 

Mezo, G., Kajtar, J., Nagy, I., Szekerke, M., and Hudecz, F. (1997) Carrier design Synthesis and conformational studies of poly[L-lysine] based branched polypeptides with hydroxyl groups. Biopolymers 42, 719-730. 

Forsch., 4 (1965) 1 G. D. Passman (Ed.)> Poly-a-amino acids protein models for conformational studies, Biological Macromolecules, Arnold (London) and M. Dekker (N.Y.) 1 (1967). 

Beychok, S. (1967). In Poly-a-amino Acids. Protein Model for Conformational Studies (G. D. Fasman, ed.), pp. 293-337. Dekker, New York. 

In conclusion, the phase behavior of symmetrically di-n-alkyl-substituted poly(silane)s and poly(silylenemethylene)s is similar both classes of polymers form the same type of mesophase, although it cannot be obtained in pure form for the poly(silylenemethylene) studied. The mobility in the mesophase, characterized by the quadmpole splitting, appears to depend strongly on the chemical structure of the backbone. For different poly(silane)s, the mobility in the crystalline phase is obviously influenced by the conformation of the backbone zW-trans vs. 73-helical) and therefore depends on the length of the side-chains. Application of pressure to poly(silane)s with 73-helical backbones leads to the formation of high-pressure crystalline modifications with dA -trans backbone conformation. The pVT studies made it possible to define the precise conditions for the pressure-induced phase transitions. 

S. Tanaka, B. Grevin, P. Rannou, H. Suzuki and S. Mashiko. Conformational studies of self-organized regioregular poly(3-dodecylthiophene)s using non-contact atomic force microscopy in ultra high vacuum condition. Thin Solid Films 499(1-2), 168-173 (2006). 

ZATION AND CONFORMATIONAL STUDIES OF POLY trans-3-ETHYL-D-PROLINE... 

Conformational studies on poly(dimethylsiloxane) suggests that it adopts an all-trans (or trans-syn) local structure and that it has an overall regular helical coiled conformation. Within these coils the inner Si-0 backbone is effectively shielded by the outer lipophilic methyl side-groups. Lack of intermolecular interaction between the methyl groups also accounts for low crystallinity in these polymers. 

Damodaran, V.B., Fee, C.J., Ruckh, T., Popat, K.C., 2010h. Conformational studies of covalently grafted poly(ethylene glycol) on modified solid matrices using X-ray photoelectron spectroscopy. Langmuir 26, 7299—7306. 

Yashima, E., Huang, S., Matsushima, T., and Okamoto, Y, Synthesis and conformational study of optically active poly(phenylacetylene) derivatives bearing a bulky substituent, Macromolecules, 28, 4184 (1995). 

Conformational studies on poly(decamethylene adipate) and poIy(tetra-methylene succinate) and the use of molecular orbital theory potential energy surfaces in determining polymer conformations for 2GT have also appeared. Crystallization, Crystallinity, and First and Second Order Transition Behaviour. The crystallization behaviour of 2GT, alone or in admixture with additives or modified by small amounts of co-monomers, continues to evoke considerable interest. Thus, X-iay fluorescence studies have been made on phenylmercurated... 

The application of the isomeric state model has recently been extended to the configurational statistics of side chains and applied to dipole moment measurements in some poly(vinyl ethers) l Experimental dipole moment measurements on a series of a,incorporated into conformational studies of the non polar polyethylene and similarly a,co-dihydroperfluoralkanes have provided information relevant to the configuration of poly(tetrafluorethylene) . ... 

Sugaj S> Nitta K, Ohno N et al. Conformational studies of poly(ethacrylic acid) in aqueous salts by potentiometric, viscometric, optical and N-NMR measurements. Colloid Polym Chem 1983 261 159-165. 

Fasman GD (1967) Poly-alpha-amino acids protein models for conformational studies. Dekker, New York... 

Conformational studies on non-natural poly-a-aminoacids containing the nitroaromatic chromophore in the side-chain, and on derivatives of [L-Trp] and [L-His] showed that, in the presence of bulky substituents the side-chain chromophores cannot assume an ordered array around the a-helical backbone. This fact is probably responsible for the absence of strong perturbation from the side-chain chromophores in the amide CD absorption region. 

Synthetic polypeptides consist of repeating sequences of certain amino acids and their structures are not as complicated as those of proteins. Eor this reason, synthetic polypeptides are sometimes used as model compounds for proteins. Their preferred conformations are classified as a helix, P sheet, 0) helix and so on. High-resolution solid-state C NMR spectroscopy has proved to be a very powerful tool for determining the structure of polypeptides in the crystalline state. Eor example, C CP MAS NMR spectra of solid poly(L-alanine) ([Ala] J show the Ca, Cp and C=0 carbon signals to be well resolved between the a helix and P sheet forms. The chemical shifts of the Ca and C=0 carbons of the a helix are displaced sig nilicantly to high frequency by 4.2 and 4.6 ppm, re spectively, relative to those of the P sheet form, while the shift of the Cp carbon of the a heUx is displaced to low frequency by about 5 ppm with respect to that of the P sheet. Eor this reason, the value of the C shift can be used to describe the local conformation. In addition, the C shifts of randomly coiled [Ala] in trifluoroacetic acid solution have values between those of the a helix and P sheet forms. The absolute C shifts of the Ca and Cp carbons are affected by the chemical structure of the individual amino acid residues and can be used effectively for conformational studies of particular amino acid residues in polypeptides and proteins. On the other hand, the C=0 shifts do not seem to be affected by residue structure and can be used for diagnosing the main chain conformation. 

Peggion, E., A. Cosani, A. S. Verdini, A. Del Pra, and M. Mammi Conformational Studies on Poly-L-Tryptophan Circular Dichroism and X-Ray Diffraction Studies. Biopolymers 6, 1477-1486 (1968). 

Peggion, E., A. Fontana, and A. Cosani Conformational Studies on a Modified Poly-L-Tryptophan Circular Dichroism and Optical Rotatory Dispersion of Poly-2-(2-nitrophenylsulfenyl)-L-tryptophan and of Random Copolymers of L-Tryptophan and 2-(2-Nitrophenylsulfenyl)-L-tryptophan. Biopolymers 7, 517-526 (1969). 

Finally, we want to describe two examples of those isolated polymer chains in a sea of solvent molecules. Polymer chains relax considerably faster in a low-molecular-weight solvent than in melts or glasses. Yet it is still almost impossible to study the conformational relaxation of a polymer chain in solvent using atomistic simulations. However, in many cases it is not the polymer dynamics that is of interest but the structure and dynamics of the solvent around the chain. Often, the first and maybe second solvation shells dominate the solvation. Two recent examples of aqueous and non-aqueous polymer solutions should illustrate this poly(ethylene oxide) (PEO) [31]... 

A number of examples have been studied in recent years, including liquid sulfur [1-3,8] and selenium [4], poly(o -methylstyrene) [5-7], polymer-like micelles [9,11], and protein filaments [12]. Besides their importance for applications, EP pose a number of basic questions concerning phase transformations, conformational and relaxational properties, dynamics, etc. which distinguish them from conventional dead polymers in which the reaction of polymerization has been terminated. EP motivate intensive research activity in this field at present. 

Furthermore it can be shown that besides the direct influence of hydrophilic and hydrophobic hydration on the conformation, the interaction of charged groups with ions is also strongly influenced by the hydration of the groups involved. Such studies were made largely by using relatively simple poly-a-aminoacids with ionogenic side chains as model substances. 

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