title: RNA backbone: consensus all-angle conformers and modular string nomenclature (an RNA Ontology Consortium contribution).
abstract: A consensus classification and nomenclature are defined for RNA backbone structure using all of the backbone torsion angles. By a consensus of several independent analysis methods, 46 discrete conformers are identified as suitably clustered in a quality-filtered, multidimensional dihedral angle distribution. Most of these conformers represent identifiable features or roles within RNA structures. The conformers are given two-character names that reflect the seven-angle delta epsilon zeta alpha beta gamma delta combinations empirically found favorable for the sugar-to-sugar "suite" unit within which the angle correlations are strongest (e.g., 1a for A-form, 5z for the start of S-motifs). Since the half-nucleotides are specified by a number for delta epsilon zeta and a lowercase letter for alpha beta gamma delta, this modular system can also be parsed to describe traditional nucleotide units (e.g., a1) or the dinucleotides (e.g., a1a1) that are especially useful at the level of crystallographic map fitting. This nomenclature can also be written as a string with two-character suite names between the uppercase letters of the base sequence (N1aG1gN1aR1aA1cN1a for a GNRA tetraloop), facilitating bioinformatic comparisons. Cluster means, standard deviations, coordinates, and examples are made available, as well as the Suitename software that assigns suite conformer names and conformer match quality (suiteness) from atomic coordinates. The RNA Ontology Consortium will combine this new backbone system with others that define base pairs, base-stacking, and hydrogen-bond relationships to provide a full description of RNA structural motifs.
authors.affiliation: Department of Biochemistry, Duke University Medical Center, Durham, North Carolina, 27710-3711, USA. jsr@kinemage.biochem.duke.edu
authors.forename: Jane S
authors.initials: JS
authors.lastname: Richardson
authors.forename: Bohdan
authors.initials: B
authors.lastname: Schneider
authors.forename: Laura W
authors.initials: LW
authors.lastname: Murray
authors.forename: Gary J
authors.initials: GJ
authors.lastname: Kapral
authors.forename: Robert M
authors.initials: RM
authors.lastname: Immormino
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Headd
authors.forename: David C
authors.initials: DC
authors.lastname: Richardson
authors.forename: Daniela
authors.initials: D
authors.lastname: Ham
authors.forename: Eli
authors.initials: E
authors.lastname: Hershkovits
authors.forename: Loren Dean
authors.initials: LD
authors.lastname: Williams
authors.forename: Kevin S
authors.initials: KS
authors.lastname: Keating
authors.forename: Anna Marie
authors.initials: AM
authors.lastname: Pyle
authors.forename: David
authors.initials: D
authors.lastname: Micallef
authors.forename: John
authors.initials: J
authors.lastname: Westbrook
authors.forename: Helen M
authors.initials: HM
authors.lastname: Berman
mesh_terms: D019295:Computational Biology; D016384:Consensus Sequence; D008958:Models, Molecular; D015394:Molecular Structure; D009690:Nucleic Acid Conformation; D012313:RNA / Q000737:chemistry*; D009626:Terminology as Topic
chemical_list: D012313:RNA