Direct phase selection of initial phases from single-wavelength anomalous dispersion (SAD) for the improvement of electron density and ab initio structure determination.

Optimization of the initial phasing has been a decisive factor in the success of the subsequent electron-density modification, model building and structure determination of biological macromolecules using the single-wavelength anomalous dispersion (SAD) method. Two possible phase solutions (φ1 and φ2) generated from two symmetric phase triangles in the Harker construction for the SAD method cause the well known phase ambiguity. A novel direct phase-selection method utilizing the θ(DS) list as a criterion to select optimized phases φ(am) from φ1 or φ2 of a subset of reflections with a high percentage of correct phases to replace the corresponding initial SAD phases φ(SAD) has been developed.

Transformation between α-helix and β-sheet structures of one and two polyglutamine peptides in explicit water molecules by replica-exchange molecular dynamics simulations.

Aggregation of polyglutamine peptides with β-sheet structures is related to some important neurodegenerative diseases such as Huntington's disease. However, it is not clear how polyglutamine peptides form the β-sheets and aggregate. To understand this problem, we performed all-atom replica-exchange molecular dynamics simulations of one and two polyglutamine peptides with 10 glutamine residues in explicit water molecules.

Oligomerization of Peptides LVEALYL and RGFFYT and Their Binding Affinity to Insulin.

Recently it has been proposed a model for fibrils of human insulin in which the fibril growth proceeds via stacking LVEALYL (fragment 11-17 from chain B of insulin) into pairs of tightly interdigitated [Formula: see text]-sheets. The experiments have also shown that LVEALYL has high propensity to self-assembly and binding to insulin. This necessitates study of oligomerization of LVEALYL and its binding affinity to full-length insulin.