Mainchain

Both methyl acrylate and butyl acrylate have been used to prepare vinylidene chloride copolymers with sufficient stability to permit thermal processing. The presence of alkyl acrylate units in the polymer mainchain limits the size of vinylidene chloride sequences and thus the propagation of degradative dehydrochlorination. More importantly it lowers the melt... 

Figure 27. Mechanism of radiation induced chain scission in PMMA. Homolysis of the mainchain-carbonyl carbon bond is indicated as the initial step. Acylcarbon-oxygen, sigma bond homolysis also occurs but rapid decarbonylation ultimately leads to the same indicated products.

Figure 2. Cross-correlations in lysozyme and (GlcNAc)e fluctuations. Protein mainchain atoms drawn in thick lines correspond to positive correlations > 0.3. These lysozyme residues are 35, 42, 44, 52, 57, 63, 73-76, 94-104, 106-110, 112 and 113. All (GlcNAc) g atoms are drawn in thin lines. The two stereo views are related by two approximately 90 rotations.

Binding to lysozyme stabilizes a conformation in site D compatible with the alternative mechanism. (i) Hg of residue D does not interact with residue E but forms a strong hydrogen bond to the mainchain 0 of residue 57, a residue involved with the unusual buried p turn in lysozyme. (ii) The value of 0 between D and E, which was -54 in the initial structure, stabilized at -62 , near the optimum of -60 for stereoelectronic assistance. 

Several asymmetric polymerization of small molecules have been reported applying the asymmetric catalysis methodology to polymer synthesis. Unique physical properties due to the mainchain stereoregularity are envisioned. 

The enantioselective addition of an allylsilane to an aldehyde catalyzed by chiral acyloxyborane (CAB) 13 is an excellent method for obtaining optically active homoallyl alcohols.Itsuno and Kumagai reported that the synthesis of a new optically active polymer with chirality on the mainchain is possible by applying this reaction to the asymmetric polymerization of bis(allylsilane) and dialdehyde (Scheme 12.11). ... 

As sparse as the dataset describing mainchain nematic LCP blends with conventional polymers is, it is rich compared to the almost non-existent data on the blending of other types of LCPs-side chain polymers, flexible spacer polymers, smectics, etc. 

Poly(Propylene). In principle, resolution of individual carbon resonances in bulk polymers allows relaxation experiments to be performed which can be interpreted in terms of mainchain and side chain motions in the solid. This is a distinct advantage over the more common proton NMR relaxation experiments where efficient spin-diffusion usually results in the averaging of the relaxation behavior over the ensemble of protons. Thus, a direct... 

Three-dimensional structures of four subtilisin-type enzymes, subtilisin BPN, 36373 subtilisin Carlsberg,37,383 thermitase,39,403 and proteinase K,40,413 are known, but that of aqualysin I has not yet been determined. The Ca atoms of the known structures were superimposed to obtain maximal overlap of the backbone structures, and large parts of all four structures overlap very well (Fig. 12.3) 423 On the basis of such analyses, structurally equivalent core residues (194 residues) are identified, and higher sequence identity was found to correspond to a closer overlap of mainchain atoms in the core (Table 12.1).423... 

Each interface contains 11 or 12 hydrogen bonds or salt bridge interactions. Although the GH/GHR complex buries more surface area into its interface, it stiU contains only 12 specific interactions. Three of the IFN-7/ IFN-7RI interactions occur between mainchain atoms in the AB loop of IFN-7 and the L2 loop of IFN-7RI. In addition to the 12 receptor-cytokine interactions, seven water molecules bridge the donor and acceptor groups of IFN-7 and IFN-7RI via hydrogen bonds (Randal and Kossiakoff, 2001). Since the B-factors for the water and protein atoms in the complex are essentially the same, the water molecules are considered to be an integral part of the interface. The presence of ordered water molecules in the IFN-7/IFN-7RI interface is not likely unique, since the IL-lO/IL-lORl interface is even more polar. However, the poorer diffraction quality of IL-10 complex crystals ( 2.9A versus 2.0A) obtained at this time prevents a detailed description of the interfacial waters. The water molecules in the... 

Only residues contributing more than 5A of surface area to the interface are included in the summaries. B.S., buried surface MC, number of mainchain hydrogen bonds MC/SC, number of mainchain/sidechain hydrogen bonds, T, total number of interactions. 

B-2006MI59 I. Tomita Polymers possessing reactive metallacycles in the mainchain, in Macromolecules Containing Metal and Metal-... 

Schubert, F. Friedrich, K. Hess, M. Kosfeld, R., "Investigations on Phase Diagrams of a Coil-Polymer (PC) and a Semiflexible Thermotropic Mainchain Polymer (PET-co-PHB) in Solution," Mol. Cryst. Liq. Cryst., 155, 477 (1988). 

Figure 23 Summary of the amino acid sequence patterns that are involved in calcium binding of the subfamilies of C-type lectins. One example in each subfamily is shown and the ligand position is marked black. The last Asp uses both oxygen atoms from the mainchain carbonyl and side chain carboxyl as the calcium ligand atoms...

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