Figure 1. Structure of the CRX HD-Ret4 complex.

A. An overview. The structure features two molecules of CRX HD bound to DNA. CRX HD is rainbow colored with the N-terminus in blue and the C-terminus in red. α3-helix of the CRX HD binds to the major DNA groove while the N terminal arm inserts into the minor groove. B. Interactions of CRX HD chain A with nucleotide bases. R43 makes hydrogen bonding interactions with adjacent T and A (TAAG), whereas N89 makes hydrogen bonding interaction with A (TAAG) in the antisense strand. C. Interactions of CRX HD chain B with nucleotide bases. R43 makes contact with TT (bold, TTAG) of sense strand and G of antisense strand (bold, TAAG), whereas N89 makes hydrogen bonding interaction with A (TAAG) in the sense strand.