PolydA and polyrA self-structured by a europium and amino acid complex

Different DNA selectivity was found for the newly synthesized europium–l-valine complex. Unexpected DNA and RNA selection results showed that europium–l-valine complex can cause single-stranded polydA and polyrA to self-structure. The sigmoidal melting curve profiles indicate the transition is cooperative, similar to the cooperative melting of a duplex DNA. This is different from another europium amino acid complex, europium–l-aspartic acid complex which can induce B-Z transition under the low salt condition. To our knowledge, there is no report to show that a metal–amino acid complex can cause the self-structuring of single-stranded DNA and RNA.