Nucleic-acid-binding properties of the C2-L1Tc nucleic acid chaperone encoded by L1Tc retrotransposon Rodríguez Heras, Sara Thomas, M.C. Macias, Francisco López López, Manuel Carlos 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. 2024-02-06T13:45:02Z 2024-02-06T13:45:02Z 2009 info:eu-repo/semantics/article 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: https://hdl.handle.net/10481/88491 10.1042/BJ20090766 eng http://creativecommons.org/licenses/by-nc-nd/4.0/ info:eu-repo/semantics/openAccess Attribution-NonCommercial-NoDerivatives 4.0 Internacional Portland Press LTD