The smaller helical repeat of poly(dA) · poly(dT) relative to DNA may reflect the wedge property of the dA · dT base pair

Abstract
A simple geometric approach is described which suggests that the smaller helical repeat of the homopolymer poly(dA) .cntdot. poly(dT) relative to DNA (10.1 against 10.6 base pairs/turn) quantitatively reflects the property of the dA .cntdot. dT base pair to behave like a wedge, of angle 11.degree., pointing towards dA.