Structure of thymidylyl-3′, 5′-deoxyadenosine

Abstract

THE triethylammonium salt of the dinucleoside phosphate, thymidylyl-3′, 5′-deoxyadenosine (TpdA) forms helical structures when aqueous solutions are allowed to evaporate¹. There are some similarities between the X-ray diffraction patterns from TpdA and those from poly(dA-dT)–poly(dA-dT), and we originally thought that the structures might be similar¹. But when the structure for poly(dA-dT)–poly(dA-dT) was proposed² it was apparent that the TpdA structure was not of the same kind. This, together with the fact that we had obtained more detailed X-ray diffraction patterns from better oriented TpdA specimens, led us to consider the different molecular model for TpdA which we describe here.