Abstract To assess the nature of the relationship between the integral conformational stability of tetrapeptides and the main types of β-turns (which are also tetrapeptides), spectrum diagrams, the as Show more
Abstract To assess the nature of the relationship between the integral conformational stability of tetrapeptides and the main types of β-turns (which are also tetrapeptides), spectrum diagrams, the asymmetry of the distribution of conformationally stable and unstable tetrapeptides have been calculated. It has been shown that β-turns of types I', II, and II' consist mainly of conformationally labile peptides; this is consistent with the context-predetermined nature of their structure. Since, as we have shown earlier, in this case the conformation is imposed by external conditions (specifically, the closure of the cycle), the prevalence of conformation-labile peptides facilitates the formation of the structure due to external factors. The type I β-turn is an exception, since peptides with different conformational lability are distributed fairly even in it. It can be assumed that the formation of the type I β-turn is not contextually determined. Show less
One of the deepest branches in the tree of life separates the Archaea from the Bacteria. These prokaryotic groups have distinct cellular systems including fundamentally different phospholipid membrane Show more
One of the deepest branches in the tree of life separates the Archaea from the Bacteria. These prokaryotic groups have distinct cellular systems including fundamentally different phospholipid membrane bilayers. This dichotomy has been termed the lipid divide and possibly bestows different biophysical and biochemical characteristics on each cell type. Classic experiments suggest that bacterial membranes (formed from lipids extracted from Escherichia coli, for example) show permeability to key metabolites comparable to archaeal Show less