Nucleic-acid-binding properties of the C2-L1Tc nucleic acid chaperone encoded by L1Tc retrotransposon
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Portland Press LTD
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2009Referencia bibliográfica
Heras SR, Thomas MC, Macias F, Patarroyo ME, Alonso C, López MC. Nucleic-acid-binding properties of the C2-L1Tc nucleic acid chaperone encoded by L1Tc retrotransposon. Biochem J. 2009 Dec 10;424(3):479-90. doi: 10.1042/BJ20090766. PMID: 19751212; PMCID: PMC2805920. Format:
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This work was supported by Plan Nacional I+D+I [MICINN (Ministerio de Ciencia e Innovaci´on)] [grant numbers BFU2006-07972, BFU2007-64999]; PAI (Plan Andaluz de Investigaci´on; Junta de Andaluc´ıa) [grant number P05-CVI-01227]; ISCIII-RETIC (Instituto de Salud Carlos III-Redes Tem´aticas de Investigaci´on Cooperativa en Salud), Spain [grant number RD06/0021/0014]; a PAI Predoctoral Fellowship [grant number P05-CVI-01227 (to F.M.)]; and Colciencias [grant number RC-2007 (to M.E.P.)].Resumen
It has been reported previously that theC2-L1Tc protein located in
the Trypanosoma cruzi LINE (long interspersed nuclear element)
L1Tc 3 terminal end has NAC (nucleic acid chaperone) activity,
an essential activity for retrotransposition of LINE-1. The C2-
L1Tc protein contains two cysteine motifs of a C2H2 type,
similar to those present in TFIIIA (transcription factor IIIA).
The cysteine motifs are flanked by positively charged amino
acid regions. The results of the present study show that the C2-
L1Tc recombinant protein has at least a 16-fold higher affinity for
single-stranded than for double-stranded nucleic acids, and that it
exhibits a clear preference for RNA binding over DNA. The C2-
L1Tc binding profile (to RNA and DNA) corresponds to a nonco-
operative-binding model. The zinc fingers present in C2-L1Tc
have a different binding affinity to nucleic acidmolecules and also
different NAC activity. The RRR and RRRKEK [NLS (nuclear
localization sequence)] sequences, aswell as the C2H2 zinc finger
located immediately downstream of these basic stretches are the
main motifs responsible for the strong affinity of C2-L1Tc to
RNA. These domains also contribute to bind single- and doublestranded
DNA and have a duplex-stabilizing effect. However, the
peptide containing the zinc finger situated towards the C-terminal
end of C2-L1Tc protein has a slight destabilization effect on
a mismatched DNA duplex and shows a strong preference for
single-stranded nucleic acids, such as C2-L1Tc. These results
provide further insight into the essential properties of the C2-
L1Tc protein as a NAC.