Structured fibrous

Elucidation of the three-dimensional structures of / -structural fibrous proteins has attracted the interest of scientists for more than 50 years. In the early days, the objects of these studies were predominandy the naturally occurring fibrous assemblies obtained from jS-silk and stretched mammalian... 

III. Diversity of -Structural Fibrous Folds Revealed by Crystallographic Studies... 

Fig. 3. Representative structures of five principal groups of //-structural fibrous folds that have recently been established by X-ray crystallographic studies. Arrows denote /3-strands. /3-Strands that belong to the same chains have the same color.

Thus, the classical pleated /1-sheet structures have now been supplemented by several new /1-structural fibrous folds that have been established by X-ray crystallographic studies. As a consequence, today, the /1-fibrous folds represent a more diverse class of fibrous structures than those defined by the a- or collagen-helices. 

We wish to dedicate this chapter to Prof. Jonathan King of MIT on the occasion of his 65th birthday in 2006 and for pointing the way in the study of /J-structured fibrous proteins. 

The partial structure of the adenovirus type 2 fiber shaft was the first /(-structured fibrous fold characterized at atomic detail. The shaft contains 15-residue sequence pseudo-repeats with an invariant glycine or proline and conserved hydrophobic amino acids (Fig. 3A Green et al., 1983). Unfolding studies led to the identification of a stable domain, consisting of amino acids 319-582, which was subcloned, expressed, and purified (Mitraki et al., 1999). Subsequently, it was crystallized, and its structure solved at 2.4-A resolution (van Raaij et al., 1999b). Its structure revealed a new fold, called the triple /(-spiral. ... 

Papanikolopoulou, K., Schoehn, G., Forge, V., Forsyth, V. T., Riekel, C., Hernandez, J.-F., Ruigrok, W. H., and Mitraki, A. (2005). Amyloid fibril formation from sequences of a natural jS-structured fibrous protein, the adenovirus fiber. J. Biol. Chem. 280, 2481-2490. 

Tertiary structure is the complete three-dimensional structure of a polypeptide chain. There are two general classes of proteins based on tertiary structure fibrous and globular. 

Liskeardite. Hydrated arsenate of Fe and A1 White, massive Structure fibrous. 

Change in the selectivity patterns of transition metal ion/H+ systems has been encountered with the amorphous and anatase types of hydrous titanium oxides with different crystallinities [24]. Potassium titanate, KjO nXi02 (n = 2-4), in particular, exhibits a layered structure. Fibrous titanic acid, H2Ti409 nHjO, is obtained by acid treatment of fibrous K2Ti409 nH20 and shows higher selectivity for K, Rb and Cs than the amorphous titanic acid [206]. 

Human elastase-1 (EC 3.4.21.36 no systematic name El) is an anionic protease belonging to the family of serine proteases. It is a carboxyendopeptidase that catalyzes hydrolysis of native elastin, the major structural fibrous protein in connective tissue, with a special affinity for the carboxyl group of alanine, valine, and leucine. 

FIGURE 18 Examples of structured fibrous catalyst supports. 

V. Holler, K. Radevik, I. Yuranov, L. Kiwi-Minsker, A. Renken, Reduction of nitrite-ions in water over Pd supported on structured fibrous materials, Appl. Catal. B Environ. 32 (2001) 143. 

L. Kiwi-Minsker, E. Joannet, A. Renken, Loop reactor staged with structured fibrous catalytic layers for liquid-phase hydrogenations, Chem. Eng. Sci. 59 (2004) 4919. 

Hydrogen-bonded networks have been prepared from compound 50, which has four pyridine units, with dicarboxylic acid 51. The complex forms network and polymeric structures. Fibrous solids are drawn from the melt state of the complexes [112]. 

Structural Polysaccharides Structural (fibrous) components are found in cell walls of plants and are represented by the linear p (1—4)-linked homopolysaccharides (a) cellulose, (b) chitin, (c) xylan, (d) mannan (10.20). Of these, cellulose is by far the most universally abundant and the most important. Starch (10.20e) derivatives are important in food technology (Chapter 12.4). 

The hydrophilic and biodegradable c-poly(glutamic acid) has been used to modify chitosan matrices, and the resulting cytocompatible composite biomaterial showed to be suitable for tissue engineering applications [56]. Another potential skin replacement blend has been prepared using chitosan and the cysteine-rich major structural fibrous protein keratin that supported fibroblast attachment and proliferation, demonstrating to be a good substrate for mammalian cell culture [137]. 

Globular proteins are soluble in polar solvents such as water and in aqueous solutions of acids and bases. Structural fibrous proteins are insoluble in water. Prolamins also dissolve in less polar solvents such as ethanol. In addition to the protein structure, solubility depends on the relative permittivity of the solvent, the pH value of the solution (the minimum solubility is at, or in the vicinity of, the isoelectric point), its ionic strength (a low concentration of salt increases the solubility by the salting-in effect, higher concentrations ofsalt reduces the solubility by the salting-out effect see Section 7.6.3.2.3), temperature and other factors. 

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