Enhanced Binding Affinity for an i-Motif DNA Substrate Exhibited by a Protein Containing Nucleobase Amino Acids
| Autor: | Zhongxian Li, Sasha M. Daskalova, Xiaoguang Bai, Poulami Talukder, Sidney M. Hecht, Shengxi Chen, Basab Roy, Larisa M. Dedkova |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
0301 basic medicine
Models Molecular Base analog 010402 general chemistry 01 natural sciences Biochemistry Catalysis Article Nucleobase 03 medical and health sciences chemistry.chemical_compound Colloid and Surface Chemistry Humans Binding site Amino Acids Nucleotide Motifs chemistry.chemical_classification Binding Sites Molecular Structure Uracil General Chemistry DNA 0104 chemical sciences Amino acid 030104 developmental biology chemistry Proto-Oncogene Proteins c-bcl-2 Nucleic acid Cytosine |
| Zdroj: | Journal of the American Chemical Society. 139(13) |
| ISSN: | 1520-5126 |
| Popis: | Several variants of a nucleic acid binding motif (RRM1) of putative transcription factor hnRNP LL containing nucleobase amino acids at specific positions have been prepared and used to study binding affinity for the BCL2 i-motif DNA. Molecular modeling suggested a number of amino acids in RRM1 likely to be involved in interaction with the i-motif DNA, and His24 and Arg26 were chosen for modification based on their potential ability to interact with G14 of the i-motif DNA. Four nucleobase amino acids were introduced into RRM1 at one or both of positions 24 and 26. The introduction of cytosine nucleobase 2 into position 24 of RRM1 increased the affinity of the modified protein for the i-motif DNA, consistent with the possible Watson–Crick interaction of 2 and G14. In comparison, the introduction of uracil nucleobase 3 had a minimal effect on DNA affinity. Two structurally simplified nucleobase analogues (1 and 4) lacking both the N-1 and the 2-oxo substituents were also introduced in lieu of His24. Again, the RRM1 analogue containing 1 exhibited enhanced affinity for the i-motif DNA, while the protein analogue containing 4 bound less tightly to the DNA substrate. Finally, the modified protein containing 1 in lieu of Arg26 also bound to the i-motif DNA more strongly than the wild-type protein, but a protein containing 1 both at positions 24 and 26 bound to the DNA less strongly than wild type. The results support the idea of using nucleobase amino acids as protein constituents for controlling and enhancing DNA–protein interaction. Finally, modification of the i-motif DNA at G14 diminished RRM1–DNA interaction, as well as the ability of nucleobase amino acid 1 to stabilize RRM1–DNA interaction. |
| Databáze: | OpenAIRE |
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