title: Evolution from DNA to RNA recognition by the bI3 LAGLIDADG maturase.
abstract: LAGLIDADG endonucleases bind across adjacent major grooves via a saddle-shaped surface and catalyze DNA cleavage. Some LAGLIDADG proteins, called maturases, facilitate splicing by group I introns, raising the issue of how a DNA-binding protein and an RNA have evolved to function together. In this report, crystallographic analysis shows that the global architecture of the bI3 maturase is unchanged from its DNA-binding homologs; in contrast, the endonuclease active site, dispensable for splicing facilitation, is efficiently compromised by a lysine residue replacing essential catalytic groups. Biochemical experiments show that the maturase binds a peripheral RNA domain 50 A from the splicing active site, exemplifying long-distance structural communication in a ribonucleoprotein complex. The bI3 maturase nucleic acid recognition saddle interacts at the RNA minor groove; thus, evolution from DNA to RNA function has been mediated by a switch from major to minor groove interaction.
authors.affiliation: Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, USA.
authors.forename: Antonella
authors.initials: A
authors.lastname: Longo
authors.forename: Christopher W
authors.initials: CW
authors.lastname: Leonard
authors.forename: Gurminder S
authors.initials: GS
authors.lastname: Bassi
authors.forename: Daniel
authors.initials: D
authors.lastname: Berndt
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Krahn
authors.forename: Traci M Tanaka
authors.initials: TM
authors.lastname: Hall
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Weeks
mesh_terms: D001483:Base Sequence; D001665:Binding Sites; D002384:Catalysis; D017124:Conserved Sequence; D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D004720:Endonucleases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D019143:Evolution, Molecular; D007438:Introns / Q000235:genetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D012313:RNA / Q000737:chemistry / Q000378:metabolism*; D012326:RNA Splicing; D013329:Structure-Activity Relationship; D013379:Substrate Specificity
chemical_list: D012313:RNA; D004247:DNA; D004720:Endonucleases