Figure 1.
Figure 1. Hoogsteen pairing of dA
with T or C. (a) Chemical structures of A and dA.
(b) Hoogsteen base pair of syn-A in syn with anti-T or anti-C.
Jagged line represents steric clash between the N6 group of A
and the N4 of C. (c) Hoogsteen base pair of dA
with T or C. Dotted lines represent hydrogen bonds and R denotes
the sugar moiety.
dA
with T or C. (a) Chemical structures of A and 
dA.
(b) Hoogsteen base pair of syn-A in syn with anti-T or anti-C.
Jagged line represents steric clash between the N6 group of A
and the N4 of C. (c) Hoogsteen base pair of