title: HORI: a web server to compute Higher Order Residue Interactions in protein structures.
abstract: BACKGROUND
  Folding of a protein into its three dimensional structure is influenced by both local and global interactions within a protein. Higher order residue interactions, like pairwise, triplet and quadruplet ones, play a vital role in attaining the stable conformation of the protein structure. It is generally agreed that higher order interactions make significant contribution to the potential energy landscape of folded proteins and therefore it is important to identify them to estimate their contributions to overall stability of a protein structure.
  
  
  RESULTS
  We developed HORI [Higher order residue interactions in proteins], a web server for the calculation of global and local higher order interactions in protein structures. The basic algorithm of HORI is designed based on the classical concept of four-body nearest-neighbour propensities of amino-acid residues. It has been proved that higher order residue interactions up to the level of quadruple interactions plays a major role in the three-dimensional structure of proteins and is an important feature that can be used in protein structure analysis.
  
  
  CONCLUSIONS
  HORI server will be a useful resource for the structural bioinformatics community to perform analysis on protein structures based on higher order residue interactions. HORI server is a highly interactive web server designed in three modules that enables the user to analyse higher order residue interactions in protein structures. HORI server is available from the URL: http://caps.ncbs.res.in/hori.
authors.affiliation: National Centre for Biological Sciences (TIFR), GKVK Campus, Bellary Road, Bangalore, 560065, India. pksmurthy@ncbs.res.in
authors.forename: Pandurangan
authors.initials: P
authors.lastname: Sundaramurthy
authors.forename: Khader
authors.initials: K
authors.lastname: Shameer
authors.forename: Raashi
authors.initials: R
authors.lastname: Sreenivasan
authors.forename: Sunita
authors.initials: S
authors.lastname: Gakkhar
authors.forename: Ramanathan
authors.initials: R
authors.lastname: Sowdhamini
mesh_terms: D030562:Databases, Protein; D020407:Internet; D008958:Models, Molecular; D011487:Protein Conformation; D017510:Protein Folding; D011506:Proteins / Q000737:chemistry*; D012984:Software; D014584:User-Computer Interface
chemical_list: D011506:Proteins