title: BIPAD: a web server for modeling bipartite sequence elements.
abstract: BACKGROUND
  Many dimeric protein complexes bind cooperatively to families of bipartite nucleic acid sequence elements, which consist of pairs of conserved half-site sequences separated by intervening distances that vary among individual sites.
  
  
  RESULTS
  We introduce the Bipad Server, a web interface to predict sequence elements embedded within unaligned sequences. Either a bipartite model, consisting of a pair of one-block position weight matrices (PWM's) with a gap distribution, or a single PWM matrix for contiguous single block motifs may be produced. The Bipad program performs multiple local alignment by entropy minimization and cyclic refinement using a stochastic greedy search strategy. The best models are refined by maximizing incremental information contents among a set of potential models with varying half site and gap lengths.
  
  
  CONCLUSIONS
  The web service generates information positional weight matrices, identifies binding site motifs, graphically represents the set of discovered elements as a sequence logo, and depicts the gap distribution as a histogram. Server performance was evaluated by generating a collection of bipartite models for distinct DNA binding proteins.
authors.affiliation: Laboratory of Human Molecular Genetics, Children's Mercy Hospital & Clinics, Kansas City, MO 64108, USA. cbi@cmh.edu
authors.forename: Chengpeng
authors.initials: C
authors.lastname: Bi
authors.forename: Peter K
authors.initials: PK
authors.lastname: Rogan
mesh_terms: D000465:Algorithms; D001483:Base Sequence; D001665:Binding Sites; D002874:Chromosome Mapping / Q000379:methods*; D003198:Computer Simulation; D004268:DNA-Binding Proteins / Q000235:genetics*; D020407:Internet; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009862:Online Systems; D011485:Protein Binding; D016415:Sequence Alignment / Q000379:methods*; D017422:Sequence Analysis, DNA / Q000379:methods*; D012689:Sequence Homology, Nucleic Acid; D012984:Software; D014157:Transcription Factors / Q000235:genetics*
chemical_list: D004268:DNA-Binding Proteins; D014157:Transcription Factors