Model of RFC bound to PCNA and DNA. (A) The RFC-PCNA-DNA model, which depicts the path of DNA bound to the clamp loader and through the clamp, combines features of a DNA-bound γ-complex structure  and an RFC-PCNA structure . (B) The α-helices lining the hole of PCNA, with the positions of the nine arginines and lysines that reside on them indicated. (C) Top and side views of the positions of the DNA molecule from the RFC-PCNA-DNA model relative to PCNA, with a model of PCNA opened by RFC overlaid upon the closed PCNA. The overlay of the open clamp shows that much of the PCNA-DNA interaction remains in place when the clamp is opened and pulled out of axis.