Institute for Data Analysis and Visualization

We consider a problem which is part of the process of determining the three-dimensional structure of a protein molecule using X-ray crystallography: given an estimated map of the electron density of the molecule as a function on three-dimensional space, we identify regions which are likely to belong to a-helices. Our approach is to compute a new kind of skeleton - the power shape - and then identify the helical substructures within the power shape with a variant of geometric hashing.