title: Structural and biochemical analyses of DNA and RNA binding by a bifunctional homing endonuclease and group I intron splicing factor.
abstract: We determined the crystal structure of a bifunctional group I intron splicing factor and homing endonuclease, termed the I-AniI maturase, in complex with its DNA target at 2.6 A resolution. The structure demonstrates the remarkable structural conservation of the beta-sheet DNA-binding motif between highly divergent enzyme subfamilies. DNA recognition by I-AniI was further studied using nucleoside deletion and DMS modification interference analyses. Correlation of these results with the crystal structure provides information on the relative importance of individual nucleotide contacts for DNA recognition. Alignment and modeling of two homologous maturases reveals conserved basic surface residues, distant from the DNA-binding surface, that might be involved in RNA binding. A point mutation that introduces a single negative charge in this region uncouples the maturase and endonuclease functions of the protein, inhibiting RNA binding and splicing while maintaining DNA binding and cleavage.
authors.affiliation: Fred Hutchinson Cancer Research Center, Division of Basic Sciences, Seattle, Washington 98109, USA.
authors.forename: Jill M
authors.initials: JM
authors.lastname: Bolduc
authors.forename: P Clint
authors.initials: PC
authors.lastname: Spiegel
authors.forename: Piyali
authors.initials: P
authors.lastname: Chatterjee
authors.forename: Kristina L
authors.initials: KL
authors.lastname: Brady
authors.forename: Maureen E
authors.initials: ME
authors.lastname: Downing
authors.forename: Mark G
authors.initials: MG
authors.lastname: Caprara
authors.forename: Richard B
authors.initials: RB
authors.lastname: Waring
authors.forename: Barry L
authors.initials: BL
authors.lastname: Stoddard
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D015252:Deoxyribonucleases, Type II Site-Specific / Q000378:metabolism*; D007438:Introns; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D012313:RNA / Q000378:metabolism*; D012326:RNA Splicing; D017386:Sequence Homology, Amino Acid
chemical_list: D012313:RNA; D004247:DNA; D015252:Deoxyribonucleases, Type II Site-Specific