Complex, macromolecular

The modem era of biochemistry and molecular biology has been shaped not least by the isolation and characterization of individual molecules. Recently, however, more and more polyfunctional macromolecular complexes are being discovered, including nonrandomly codistributed membrane-bound proteins [41], These are made up of several individual proteins, which can assemble spontaneously, possibly in the presence of a lipid membrane or an element of the cytoskeleton [42] which are themselves supramolecular complexes. Some of these complexes, e.g. snail haemocyanin [4o], are merely assembled from a very large number of identical subunits vimses are much larger and more elaborate and we are still some way from understanding the processes controlling the assembly of the wonderfully intricate and beautiful stmctures responsible for the iridescent colours of butterflies and moths [44]. 

As a polycation, chitosan spontaneously forms macromolecular complexes upon reaction with anionic polyelectrolytes. These complexes are generally water-insoluble and form hydrogels [90,91]. A variety of polyelectrolytes can be obtained by changing the chemical structure of component polymers, such as molecular weight, flexibility, fimctional group structure, charge density, hydrophilicity and hydrophobicity, stereoregularity, and compatibility, as... 

Spliceosome The macromolecular complex responsible for precursor mRNA splicing. The spliceosome consists of at least five small nuclear RNAs (snRNA Ul, U2, U4, U5, and U6) and many proteins. 

As with the other monoamines, 5-HT is found primarily in storage vesicles (30-35 nm diameter) where serotonin-binding proteins (SBPs) have also been identified. These seem to form a macromolecular complex with 5-HT. In fact, three such proteins have now been characterised, but only one of them, 45kDa SBP, appears to be secreted into the synapse along with 5-HT. Whether they serve any role other than forming an osmotically inert storage matrix for 5-HT is unknown. 

Macromolecular complexing agents have featured a good deal in recent research. Although they do not yet appear to have attained any significant commercial use, they possess interesting properties, not least their environmental advantages, that offer potential for future exploitation. 

Not only do the macromolecular components which are the direct products of the genes participate in the formation of complex pathways and networks, they can also assemble to form macromolecular complexes and micromachines . Some of these micromachines are now well known, such as ATPase, some parts of which turn like a rotor in the mitochondrial membrane to generate the energy of the cell, or the micromachines responsible for transcription or DNA replication. Some others are less known, but play critical roles, such as the complex that forms in the cell membrane and can induce the cell to commit suicide . 

The principles of organization of molecular components described here mean that it is impossible to predict the functioning of these networks and macromolecular complexes from knowledge of the elementary components. 

The addition of PEG to the gels was critical because the PEG chains participate in the macromolecular complexes, function as a peptide stabilizer and enhance the mucoadhesive characteristics of the gels. In this work, strong dose-dependent hypoglycemic effects were observed in healthy and diabetic rats following oral administration of these gels. 

Varadaraj R, Branham KD, McCormick CL, Bock J (1994) Analysis of hydrophobi-cally associating copolymers utilizing spectroscopic probes and labels. In Dubin P, Bock J, Davis R, Schulz DN, Thies C (eds) Macromolecular complexes in chemistry and biology. Springer-Verlag, Berlin, p 15... 

Ion channels are macromolecular complexes that form aqueous pores in the lipid membrane 99... 

Ion channels are macromolecular complexes that form aqueous pores in the lipid membrane. We have learned much about ion channel function from voltage clamp and patch clamp studies on channels still imbedded in native cell membranes [1-6, 8]. A diversity of channel types was discovered in the different cells in the body, where the repertoire of functioning channels is adapted to the special roles each cell plays [5]. The principal voltage-gated ones are the Na+, K+ and Ca2+ channels, and most of these are opened by membrane depolarizations. Figure 6-5A summarizes the major functional properties of a voltage-gated... 

Tytell, M., Black, M. M., Garner, J. A. and Lasek, R. J. Axonal transport Each of the major rate components consist of distinct macromolecular complexes. Science 214 179-181, 1981. 

Meadows LS, Isom LL (2005) Sodium channels as macromolecular complexes implications for inherited arrhythmia syndromes. Cardiovasc Res 67 448 158... 

Galceran, J., Cecilia, J., Salvador, J., Monne, J., Torrent, M., Companys, E., Puy, J., Garces, J. L. and Mas, F. (1999). Voltammetric currents for any ligand-to-metal concentration ratio in fully labile metal-macromolecular complexation. Easy computations, analytical properties of the currents and a graphical method to estimate the stability constant, J. Electroanal. Chem., 472, 42-52. 

Conclusion/Outlook - Toward Higher Macromolecular Complexity in the Twenty-first Century... 

Macromolecular complexes of proteins and carbohydrate present in the ECM serve not only as adhesive keeping cells in their correct positions but also facilitate control of cell activity by signalling through membrane proteins such as the integrin family of receptors. Glycoproteins are mainly protein with covalently attached carbohydrate whereas proteoglycans are predominantly complex carbohydrates secured on a protein framework. 

Wall ME, Gallagher SC, Trewhalla J (2000) Large scale shape changes in proteins and macromolecular complexes. Ann Rev Chem 51 355... 

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