Proteinaceous network

The nuclear lamina lies subjacent to the inner nuclear membrane (see Fig. 1 in the chapter by Berrios, this volume) it is a proteinaceous network composed of intermediate filament-like fibrils and is thought to provide structural support to the interphase nucleus. Results of previous studies suggest that the lamina binds specific loci on chromosomes and may thus play a role in organizing the genome within nuclei (Lud rus et al., 1992,1994 Baricheva et al, 19% Zhao et aL, 19% Rzepecki et al., 1997 Sharakhov et al., 1997). Other results suggest that the lamina may also be involved in DNA replication (see, e.g., Moir et al., 1994). The lamina appears to anchor nuclear pore complexes physically. 

In many cases, the matrices and scaffolds of these implants would ideally be made of biodegradable pol5miers. These pol5mciers should mimic the functions of the extracellular matrix (ECM). This is a soft, tough and elastomeric proteinaceous network that provides mechanical stability and structural integrity to tissues and organs. 

R. Lletf, L.A. Sarabia, M.C. Ortiz, R. Todeschini, M.P. Colombini, Application of the Kohonen Artifical Neural Network in the Identification of Proteinaceous Binders in Samples of Panel Painting using Gas Chromatography Mass Spectrometry, Analyst, 128, 281 286 (2003). 

In order to have a metabolic and enzymatic system, it would be necessary to have proteinaceous enzymes which can catalyse the synthesis of other enzymes, and for this they should be capable of making peptide bonds. Such systems have not been found in nature, so far, but according to Stuart Kauffman (1986) they could have existed in the past, and in primitive compartments could have produced autocatalytic networks which had the potential to jump from chaos to order. Even if we admit that those enzymes existed, however, we still have the problem of accounting for the origin of the complex autocatalytic networks that housed them. 

In a recent NMR study, Derenne et al.(77) obtained evidence for non hydrolyzable amide structures in refractory fractions of the algae Scenedesmus quadricauda. The solid-state NMR spectra showed a major peak around -260 ppm for amides accompanied by a peak around -195 ppm for substituted pyrroles and a shoulder at -235 ppm assigned to unsubstituted pyrroles of the insoluble residue. The authors suggest, that the amides are protected by association with long polymethylenic chains within a macromolecular network. Knicker and Hatcher offer an alternative explanation,- that protection of amide functional groups as part of proteinaceous material are affected by encapsulation within the macromolecular matrix forming sedimentaryhumic material(7.. ... 

Cytoplasm was once believed to be a structureless solution in which the nucleus was suspended. Experiments have revealed not only the extensive membrane system and the membranous organelles just described, but also an intricate supportive network of proteinaceous fibers and filaments called the cytoskeleton (Figure 2.27). Components of the cytoskeleton include microtubules, microfilaments, and intermediate fibers. 

The stmctures of HA and FA are not yet determined. A combination of many techniques is required to determine the structure of HSs. Schulten et al. have employed p)>Tolysis-gas chromatography with electron impact and field ionisation mass spectrometry (Py-GC/MS), in-source pyrolysis-field ionisation mass spectrometry (Py-FIMS), CP/MS NMR, oxidative and reductive degradation, colloid chemical methods, and electron microscopy to develop a carbon network structure for soil HS (Schulten (1994), Schulten and Schnitzer (1993)). The elemental composition of FLA was C3()8H32s09oN5 fot MW of 5540 Da. This indicates of the complexity of such compounds and the extensive techniques required. If carbohydrates or proteinaceous materials are bonded covalently with HA, %C content decreases and %0 content increases. 

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