Supramolecular, generally structures

Microtubules in the cytoskeleton and mitotic apparatus are also in a state of dynamic equilibrium and flux with unpolymerized tubulin, and tubulin appears to be an excellent example of the proteins which Pauling (1953) postulated to exist as globular protomers or as insoluble, fibrous, supramolecular structures akin to unpolymerized and polymeric hemoglobin S. The current view of the microtubule cytoskeleton in nondividing celb comes from the development of tubulin-specific antibodies for indirect immunofluorescent localization of microtubules (Fuller et al., 1975 Weber et al., 1975). The general structural features of such cyto-... 

The helicates have attracted considerable attention in supramolecular chemistry as good examples of products of self-assembly reactions in which a number of components are assembled to give a unique structure in high yield. The general structure of a helicate is given in Figure 9. 

In general, structures of supramolecular objects of hybrid proteins on the surfaces were individual for each set of fused molecules and different from lysozyme fibrils. Ball-like objects were the most typical objects detected on the surfaces in the experiments with the hybrid proteins. The structure is illustrated in Fig. 3a by typical SPM image. The size of the balls in these structures seemed dependent on the type of hybrid protein but quantitative description of the dependence requires additional studies. 

Fig. 26 General structure of the mechanically responsive Pd-phosphine-containing metallo-supramolecular polymers studied by Sijbesma and co-workers [86]...

Polyoxometalates also play an important role in the selection of a metal ion for its complete encapsulation in the cavity of a crown ether to form an unusual supramolecular cation structure. For example, the crown ethers (macrocyclic polyethers), generally, do not readily form complexes with first-row transition metals in their low oxidation states because such metal ions provide only soft coordination (acceptor) sites and crown ethers have hard donor atoms. Naturally, only a few first-row transition metal rown ether complexes had been structurally characterized in which a direct bond formation between a transition metal and the crown ether oxygen atoms became possible rare examples of this kind are offered by the smaller ring crown ethers (e.g., 15-crown-5 and... 

Ribosomes, the supramolecular assemblies where protein synthesis occurs, are about 65% RNA of the ribosomal RNA type. Ribosomal RNA (rRNA) molecules fold into characteristic secondary structures as a consequence of intramolecular hydrogen bond interactions (marginal figure). The different species of rRNA are generally referred to according to their sedimentation coefficients (see the Appendix to Chapter 5), which are a rough measure of their relative size (Table 11.2 and Figure 11.25). 

The combined features of structural adaptation in a specific hybrid nanospace and of a dynamic supramolecular selection process make the dynamic-site membranes, presented in the third part, of general interest for the development of a specific approach toward nanomembranes of increasing structural selectivity. From the conceptual point of view these membranes express a synergistic adaptative behavior the addition of the most suitable alkali ion drives a constitutional evolution of the membrane toward the selection and amplification of a specific transport crown-ether superstructure in the presence of the solute that promoted its generation in the first place. It embodies a constitutional selfreorganization (self-adaptation) of the membrane configuration producing an adaptative response in the presence of its solute. This is the first example of dynamic smart membranes where a solute induces the preparation of its own selective membrane. 

As mentioned above (Section 2.1), inorganic and organic halides of TeIV are generally exhibiting halide-bridged supramolecular structures.1 3,6,7 Both Te X and X- X contacts are occurring, depending on the substitution patterns of compounds R4 TeX (n = 3, 2, 1). 

Here, following the works of J.H. De Boer (Delft, The Netherlands, see elsewhere [1,2]), by texture one means the individual geometrical structure of catalysts, supports, and other porous systems (PSs) at the level of pores, particles and their ensembles (i.e., on a supramolecular level scale of 1 nm and larger). In a more complete interpretation, texture includes morphology of porous space and the skeleton of a condensed (solid or sometimes liquid) phase, the shape, size, interconnectivity, and distribution of individual supramolecular elements of the system particles and pores (or voids) between particles, various phases, etc. In turn, texturology also involves general laws of texture formation and methods for its characterization [3],... 

The model of clusters or ensembles of sites and bonds (secondary supramolecular structure), whose size and structure are determined on the scale of a process under consideration. At this level, the local values of coordination numbers of the lattices of pores and particles, that is, number of bonds per one site, morphology of clusters, etc. are important. Examples of the problems at this level are capillary condensation or, in a general case, distribution of the condensed phase, entered into the porous space with limited filling of the pore volume, intermediate stages of sintering, drying, etc. 

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