title: Using diffusion distances for flexible molecular shape comparison.
abstract: BACKGROUND
  Many molecules are flexible and undergo significant shape deformation as part of their function, and yet most existing molecular shape comparison (MSC) methods treat them as rigid bodies, which may lead to incorrect shape recognition.
  
  
  RESULTS
  In this paper, we present a new shape descriptor, named Diffusion Distance Shape Descriptor (DDSD), for comparing 3D shapes of flexible molecules. The diffusion distance in our work is considered as an average length of paths connecting two landmark points on the molecular shape in a sense of inner distances. The diffusion distance is robust to flexible shape deformation, in particular to topological changes, and it reflects well the molecular structure and deformation without explicit decomposition. Our DDSD is stored as a histogram which is a probability distribution of diffusion distances between all sample point pairs on the molecular surface. Finally, the problem of flexible MSC is reduced to comparison of DDSD histograms.
  
  
  CONCLUSIONS
  We illustrate that DDSD is insensitive to shape deformation of flexible molecules and more effective at capturing molecular structures than traditional shape descriptors. The presented algorithm is robust and does not require any prior knowledge of the flexible regions.
authors.affiliation: School of Software, Tsinghua University, Beijing 100084, China. liuyushen00@gmail.com
authors.forename: Yu-Shen
authors.initials: YS
authors.lastname: Liu
authors.forename: Qi
authors.initials: Q
authors.lastname: Li
authors.forename: Guo-Qin
authors.initials: GQ
authors.lastname: Zheng
authors.forename: Karthik
authors.initials: K
authors.lastname: Ramani
authors.forename: William
authors.initials: W
authors.lastname: Benjamin
mesh_terms: D000465:Algorithms; D003198:Computer Simulation; D016208:Databases, Factual; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008958:Models, Molecular; D008968:Molecular Conformation; D010363:Pattern Recognition, Automated / Q000379:methods; D011487:Protein Conformation; D011506:Proteins / Q000737:chemistry
chemical_list: D011506:Proteins