The Rna Binding Subset of Adenosine Antibodies

Abstract

Hapten specific antibodies were elicited against adenosine-BSA conjugate (Ado*-BSA) in rats. By radiohapten assay, two major populations of hapten specific antibodies were identified. They were directed against either adenosine trialcohol(A^ox-red) or morpholino-adenosine(Morph-Ade). The association constant (Ka) for the ³H-A^ox-red binding population was determined to be 1.02 × 10⁷ M^-1. Majority of the A^ox-red specific antibodies were crossreactive with Morph-Ade, but they did not cross-react at all with adenosine(A) or deoxyadenosine(dA). ³H-A binding subsets were actually Morph-Ade specific and constitute less than 10% of the hapten specific antibodies. The Ka value for the ³H-A binding was determined to be 4.5 × 10⁶ M^-1. A very minor and highly cross-reactive subset of Morph-Ade specific antibodies participate in RNA binding. Though a larger proportion of Morph-Ade specific antibodies interact with ³H-A, only a fraction of them bind to RNA. The extreme crossreactivity and hence, the highly adaptive nature of the binding sites of the antibodies interacting with RNA, might be a stringent requirement for recognising adenine residues of nucleic acids in solution.