Fig. S4.

The active site of chain A of the LipA intermediate-bound structure. (A) Distances between C5′ of 5′-dA and its reaction partners and between C8 of substrate and its possible reaction partners. Other distances are listed in Table S2. (B) The observed stereochemistry of the LipA reaction—abstraction of the pro-R hydrogen atom and inversion of configuration at C6—is reflected in the intermediate-bound structure. Here, a riding hydrogen atom added to C6 is within van der Waals distance of C5′ of 5′-dA.