Translocation, biological models

Translocation also referred to as reciprocal translocation. See Fraccaro, M Chromosome abnormalities and gamete production in man. Differentiation 23 (SuppL), S40-S43,1983 Davis, J.R., Rogers, B.B., Hagaman, R.M., Thies, C.A., and Veomett, I.C., Balanced reciprocal translocations risk factors for aneuploid segregant viability, Clin. Genet. 27, 1-19, 1985 Greaves, M.F., Biological models for leukemia and lymphoma, lARC Sci. Publ. 157, 351-372, 2004 ... 

In order to address the characteristics of biological models, we have to first define the basic principles of biological systems that a supramolecular model may mimic. Among the most important are selective molecular recognition of a molecular entity selective and highly accelerated modification of a substrate (typieal role of enzymes) compartmentalization and selective translocation of chemical species across boundaries (typieal role of biomembranes) harvesting and transformation of energy and self-replication. 

Biological. [ C]Phorate degraded in a model ecosystem consisting of soil, plants, and water (Lichtenstein et al, 1974). Under both nonpercolating and percolating water conditions, 12% of the applied amount migrated downward as the corresponding sulfone and sulfoxide. Phorate was absorbed in the roots of corn and was transformed primarily to the sulfone with trace amounts of the sulfoxide. Translocation of radioactive insecticide to the leaves was also observed but the major products were identified as phoratoxon sulfone and phoratoxon sulfoxide. 

Braun-Sand, S., Strajbl, M. and Warshel, A. (2004). Studies of proton translocations in biological systems simulating proton transport in carbonic anhydrase by EVB based models. Biophys. J. 87, 2221-2239... 

Exported proteins must cross a biological membrane, which is composed largely of lipids and proteins. Is the translocation site made of lipids or protein The membrane trigger hypothesis, the helical hairpin hypothesis, the domain model, and the model of Nesmayanova postulate that protein translocation occurs directly through the lipid bilayer and that no proteinaceous export site is necessary. Other proteins may be needed for recognition, and signal peptidase is required for removal of the signal sequence after export. Evidence for a lipid translocation site comes primarily from experiments in reconstituted export systems in Wickner s laboratory. It has been shown that the precursors of M13... 

All the signaling mechanisms of the computational model are defined explicitly in terms of molecular interactions, that is, the model does not rely on abstract amplification or translocation modules that, while reducing the number of hypotheses contained in the model, would also diminish its biological relevance and, importantly, its predictive power. As a consequence of this approach we had to deal with a relatively large number of molecular players and an even much larger number of resulting multimolecular complexes. 

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