in this study, the effect of the secondary structure of the protein on the acid strength of three structures of random (r), alpha helix (α) and beta sheet (b) were investigated theoretically. these structures are related to the cationic amino acids of histidine and lysine in the polypeptide chain of eight-glycine residue. computational methods at the hf, b3lyp, x3lyp and m05-2x levels in the ga...

Beta-pleated-sheet crystals are among the most stable of protein secondary structures, and are responsible for the remarkable physical properties of many fibrous proteins, such as silk, or proteins forming plaques as in Alzheimer's disease. Previous thinking, and the accepted paradigm, was that beta-pleated-sheet crystals in the dry solid state were so stable they would not melt upon input of h...

When beta-pleated sheets pack face to face in proteins, the angle between the strand directions of the two beta-sheets is observed to be near -30 degrees . We propose a simple model for beta-sheet-to-beta-sheet packing in concanavalin A, plastocyanin, gamma-crystallin, superoxide dismutase, prealbumin, and the immunoglobin fragment V(REI). This model shows how the observed relative orientation ...

MOTIVATION Despite the importance of beta-sheets as building blocks in proteins and also toxic elements in the pathological disorders, ranging from Alzheimer's disease to mad cow disease, the principles underlying their stability are not well understood. Non-random beta-sheet propensities of amino acids have been revealed both by their distinct statistical preferences within known protein struc...

The design and characterization of an open eight-stranded beta-sheet in a synthetic, 2-fold symmetric 70-residue peptide is described. The design strategy involves the generation of a 35-residue four-stranded beta-sheet peptide in which successive hairpins are nucleated by appropriately positioned (D)Pro-Xxx sequences. Oxidative dimerization using a single Cys residue positioned at the center o...

Autonomously folding beta-hairpins have recently emerged as powerful tools for elucidating the origins of antiparallel beta-sheet folding preferences. Analysis of such model systems has suggested four potential sources of beta-sheet stability: (1) the conformational propensity of the loop segment that connects adjacent strands; (2) favorable contacts between side-chains on adjacent strands; (3)...

It has been found that the self-assembling peptide RADA 16-I forms a beta-sheet structure and self-assembles into nanofibers and scaffolds in favor of cell growth, hemostasis and tissue-injury repair. But its biophysical and morphological properties, especially for its beta-sheet and self-assembling properties in heat- and pH-denatured conditions, remain largely unclear. In order to better unde...

Design of complex alpha-beta protein topologies poses a challenge because of the large number of alternative packing arrangements. A similar challenge presumably limited the emergence of large and complex protein topologies in evolution. Here, we demonstrate that protein topologies with six and seven-stranded beta sheets can be designed by insertion of one de novo designed beta sheet containing...

Laminar, or sheet, architecture of the left ventricle (LV) is a structural basis for normal systolic and diastolic LV dynamics, but transmural sheet orientations remain incompletely characterized. We directly measured the transmural distribution of sheet angles in the ovine anterolateral LV wall. Ten Dorsett-hybrid sheep hearts were perfusion fixed in situ with 5% buffered glutaraldehyde at end...

We describe experiments that probe whether antiparallel beta-sheet secondary structure becomes more stable as the number of strands increases. Several groups, including ours, have explored this issue with peptides designed to adopt three-stranded beta-sheet conformations, but the conclusions have not been consistent. In this study, we examine the effect on conformational stability of beta-sheet...