Unexpected active site in Trypanosoma brucei flap endonuclease
نویسندگان
چکیده
منابع مشابه
Active site substitutions delineate distinct classes of eubacterial flap endonuclease
FENs (flap endonucleases) play essential roles in DNA replication, pivotally in the resolution of Okazaki fragments. In eubacteria, DNA PolI (polymerase I) contains a flap processing domain, the N-terminal 5'-->3' exonuclease. We present evidence of paralogous FEN-encoding genes present in many eubacteria. Two distinct classes of these independent FEN-encoding genes exist with four groups of eu...
متن کاملEndonuclease associations with three distinct editosomes in Trypanosoma brucei.
Three distinct editosomes, typified by mutually exclusive KREN1, KREN2, or KREN3 endonucleases, are essential for mitochondrial RNA editing in Trypanosoma brucei. The three editosomes differ in substrate endoribonucleolytic cleavage specificity, which may reflect the vast number of editing sites that need insertion or deletion of uridine nucleotides (Us). Each editosome requires the single RNas...
متن کاملAn essential RNase III insertion editing endonuclease in Trypanosoma brucei.
RNA editing adds and deletes uridine nucleotides in many preedited mRNAs to create translatable mRNAs in the mitochondria of the parasite Trypanosoma brucei. Kinetoplastid RNA editing protein B3 (KREPB3, formerly TbMP61) is part of the multiprotein complex that catalyzes editing in T. brucei and contains an RNase III motif that suggests nuclease function. Repression of KREPB3 expression, either...
متن کاملFunctional analysis of point mutations in human flap endonuclease-1 active site.
Human flap endonuclease-1 (hFEN-1) is highly homologous to human XPG, Saccharomyces cerevisiae RAD2 and S.cerevisiae RTH1 and shares structural and functional similarity with viral exonucleases such as T4 RNase H, T5 exonuclease and prokaryotic DNA polymerase 5'nucleases. Sequence alignment of 18 structure-specific nucleases revealed two conserved nuclease domains with seven conserved carboxyl ...
متن کاملObservation of unpaired substrate DNA in the flap endonuclease-1 active site
The structure- and strand-specific phosphodiesterase flap endonuclease-1 (FEN1), the prototypical 5'-nuclease, catalyzes the essential removal of 5'-single-stranded flaps during replication and repair. FEN1 achieves this by selectively catalyzing hydrolysis one nucleotide into the duplex region of substrates, always targeting the 5'-strand. This specificity is proposed to arise by unpairing the...
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ژورنال
عنوان ژورنال: Acta Crystallographica Section A Foundations and Advances
سال: 2016
ISSN: 2053-2733
DOI: 10.1107/s2053273316096157