into a right-handed helix 7 nm in diameter. Each turn of the helix consists of 3 '/8 subunits. The quaternary structure is highly resistant to disruption but can be dissociated into its subunits by being boiled in acid (10) or

for a model of DNA gyrase action that assumes existence of a free loop between the G- and T- DNA segments participating in the reaction. A popular model of this type assumed that the selectivity can be provided by the conformation of the DNA segment wrapped around the enzyme into the right-handed helix

. The threadlike elements in the axoplasm are twisted as a whole into a steep, right-handed helix. In a peripheral ectoplasmic region, the elements are more parallel to one another and more densely packed than in a central endoplasmic core. The threadlike elements can be resolved into a hierarchy of decreasing

preferring helical conformations in both solution and crystalline states. A structural transition to a frayed right-handed helix is observed in (CD3),SO. These results suggest that nonhelical conformations may be important in Gly-rich peptides containing Aib. Further, the presence of amino acids

loading subunits. Indeed, molecular simulations of PCNA indicate that it springs open out-of-plane with a strong tendency to form a right-handed helix (21). In addition, electron microscopic reconstruction of an archael RFC-PCNA-ATP␥S-DNA complex provides direct visual evidence for an open clamp in a

is found to be stable in peptide B with starting geometry of a right handed helix, while in the case peptide A, the helical length is short. The interactions of water molecules at terminals, side chain-backbone interactions and hydrogen bonds provide stability to resultant conformation. The adopted helix

enhancements in steady state luminescent intensity and a lengthening of luminescent lifetimes are seen for ruthenium enantiomers with Z-DNA as for B-DNA but with enantio-selectivities reversed. Greater enhancements are seen for A-isomers with the right-handed helix but for A-isomers with the left-handed helix

Abstract: A reasonable description of the conformation energies of each of the amino acids is crucial for modeling protein structures and dynamics. We here used 20 tetrapeptides (ACE-ALA-X-ALA-NME, X) one of 20 amino acids) in 5 conformations (right-handed helix (RR), left-handed helix (RL), -sheet

noncentrosymmetric dimers incorporating R2 2(10) ring motifs. These nonbonding interactions propagate along the 61 screw axis normal to the molecular twofold axis, resulting in a single-stranded right-handed helix parallel to [001]. In the crystal, helices are arranged side-by-side and interact through – contacts

the crystal structure at 0.95 AÊ resolution of a parallel-stranded tetraplex formed by the hexanucleotide d(TG4T) in the presence of sodium ions. The four strands form a right-handed helix that is stabil-ized by hydrogen-bonding tetrads of co-planar guanine bases. Well-resolved sodium ions are found between