1p8k
From Proteopedia
The structure and DNA recognition of a bifunctional homing endonuclease and group I intron splicing factor
Structural highlights
Function[ANI1_EMEND] Mitochondrial DNA endonuclease and mRNA maturase involved in intron homing and required for splicing of the cytochrome b (cobA) gene intron, containing its own coding sequence. The protein stimulates the intrinsic ribozyme activity of the intron through binding to and stabilizing specific secondary and tertiary structure elements in the RNA. As an endonuclease it introduces a specific double-strand break at the junction of the two exons the cobA gene and thus mediates the insertion of an intron, containing its own coding sequence (group I intron), into an intronless gene. Recognizes with limited specificity and cleaves the sequence 5'-GAGGAGGTTTCTCTGTA-3'. The proteins RNA and DNA recognition and binding surfaces are independent.[1] [2] [3] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedWe 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. Structural and biochemical analyses of DNA and RNA binding by a bifunctional homing endonuclease and group I intron splicing factor.,Bolduc JM, Spiegel PC, Chatterjee P, Brady KL, Downing ME, Caprara MG, Waring RB, Stoddard BL Genes Dev. 2003 Dec 1;17(23):2875-88. Epub 2003 Nov 21. PMID:14633971[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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