Quantitative analysis of the interaction between l-methionine derivative and oligonucleotides.

This study explores the use of l-methionine derivative as a potential affinity ligand for nucleic acids purification. The l-methionine derivative is synthesized by activation of the carboxylic acid group with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide follow by immobilization on amine sensor surface, previously activated and treated with ethylenediamine. Their affinity towards oligonucleotides has been determined by surface plasmon resonance biosensor. The highest affinity is found for cytosine and thymine, followed by adenine, whereas the lowest affinity is found for guanine. For hetero-oligonucleotides the affinity order is CCCTTT > CCCAAA ≈ AAATTT > GGGTTT, showing that nucleotides with cytosine have the highest affinity, and the presence of guanine reduces the affinity, corroborating with the results obtained with homo-oligonucleotides.