title: An effective sequence-alignment-free superpositioning of pairwise or multiple structures with missing data.
abstract: BACKGROUND
  Superpositioning is an important problem in structural biology. Determining an optimal superposition requires a one-to-one correspondence between the atoms of two proteins structures. However, in practice, some atoms are missing from their original structures. Current superposition implementations address the missing data crudely by ignoring such atoms from their structures.
  
  
  RESULTS
  In this paper, we propose an effective method for superpositioning pairwise and multiple structures without sequence alignment. It is a two-stage procedure including data reduction and data registration.
  
  
  CONCLUSIONS
  Numerical experiments demonstrated that our method is effective and efficient. The code package of protein structure superposition method for addressing the cases with missing data is implemented by MATLAB, and it is freely available from: http://sourceforge.net/projects/pssm123/files/?source=navbar.
authors.affiliation: Human Genetics Resource Center, National Research Institute for Family Planning, Beijing, 100081 China ; Graduate School of Peking Union Medical College, Beijing, 100730 China.
authors.forename: Jianbo
authors.initials: J
authors.lastname: Lu
authors.affiliation: National Center for Mathematics and Interdisciplinary Sciences, Academy of Mathematics and Systems Science, Chinese Academy of Sciences, Beijing, 100190 China.
authors.forename: Guoliang
authors.initials: G
authors.lastname: Xu
authors.affiliation: National Center for Mathematics and Interdisciplinary Sciences, Academy of Mathematics and Systems Science, Chinese Academy of Sciences, Beijing, 100190 China.
authors.forename: Shihua
authors.initials: S
authors.lastname: Zhang
authors.affiliation: National Center for Mathematics and Interdisciplinary Sciences, Academy of Mathematics and Systems Science, Chinese Academy of Sciences, Beijing, 100190 China.
authors.forename: Benzhuo
authors.initials: B
authors.lastname: Lu
keywords: Iterative closest point; Protein structure alignment; Superposition