Erratum to "Effect of supercoiling on formation of protein-mediated DNA loops"
by PK Purohit and PC Nelson (Physical Review E 74, 061907 2006):

Figure 2a was incorrectly attributed to A Balaeff, L Mahadevan, and K Schulten, Phys Rev Lett 1999. The correct citation is 
Alexander Balaeff, L. Mahadevan, and Klaus Schulten. Modeling DNA loops using the theory of elasticity. Physical Review E, 73:031919, 2006
(our reference 32).

In addition, the figure caption should have clearly stated that figure 2a was taken in its entirety from the above article. It was reproduced in our article to illustrate the relevance of the simplified mathematical problem we discussed to gene regulation, and to illustrate the existence of much more detailed models than the one we gave.