title: Towards improved quality of GPCR models by usage of multiple templates and profile-profile comparison.
abstract: G-protein coupled receptors (GPCRs) are targets of nearly one third of the drugs at the current pharmaceutical market. Despite their importance in many cellular processes the crystal structures are available for less than 20 unique GPCRs of the Rhodopsin-like class. Fortunately, even though involved in different signaling cascades, this large group of membrane proteins has preserved a uniform structure comprising seven transmembrane helices that allows quite reliable comparative modeling. Nevertheless, low sequence similarity between the GPCR family members is still a serious obstacle not only in template selection but also in providing theoretical models of acceptable quality. An additional level of difficulty is the prediction of kinks and bulges in transmembrane helices. Usage of multiple templates and generation of alignments based on sequence profiles may increase the rate of success in difficult cases of comparative modeling in which the sequence similarity between GPCRs is exceptionally low. Here, we present GPCRM, a novel method for fast and accurate generation of GPCR models using averaging of multiple template structures and profile-profile comparison. In particular, GPCRM is the first GPCR structure predictor incorporating two distinct loop modeling techniques: Modeller and Rosetta together with the filtering of models based on the Z-coordinate. We tested our approach on all unique GPCR structures determined to date and report its performance in comparison with other computational methods targeting the Rhodopsin-like class. We also provide a database of precomputed GPCR models of the human receptors from that class.
  
  
  BACKGROUND
  GPCRM SERVER AND DATABASE: http://gpcrm.biomodellab.eu.
authors.affiliation: International Institute of Molecular and Cell Biology, Warsaw, Poland. dlatek@iimcb.gov.pl
authors.forename: Dorota
authors.initials: D
authors.lastname: Latek
authors.forename: Pawel
authors.initials: P
authors.lastname: Pasznik
authors.forename: Teresa
authors.initials: T
authors.lastname: Carlomagno
authors.forename: Slawomir
authors.initials: S
authors.lastname: Filipek
mesh_terms: D058671:Adrenergic beta-1 Receptor Antagonists / Q000737:chemistry; D006801:Humans; D008958:Models, Molecular; D062105:Molecular Docking Simulation; D011487:Protein Conformation; D043705:Receptor, Adenosine A2A / Q000737:chemistry; D018342:Receptors, Adrenergic, beta-1 / Q000737:chemistry; D018167:Receptors, Calcitriol / Q000737:chemistry; D043562:Receptors, G-Protein-Coupled / Q000737:chemistry*; D012243:Rhodopsin / Q000737:chemistry
chemical_list: D058671:Adrenergic beta-1 Receptor Antagonists; D043705:Receptor, Adenosine A2A; D018342:Receptors, Adrenergic, beta-1; D018167:Receptors, Calcitriol; D043562:Receptors, G-Protein-Coupled; D012243:Rhodopsin