Generation of noble-gas binding sites for crystallographic phasing using site-directed mutagenesis

A novel approach for de novo phase determination using site-directed mutagenesis to generate noble-gas binding sites in proteins is described. MIR phases from xenon derivatives obtained using this method compare favorably with MAD phases from selenomethionine substitution.

Thermolysin in the absence of substrate has an open conformation

The structure of thermolysin in the absence of substrate has been determined in a new crystal form. The enzyme takes an open conformation consistent with hinge-bending during the catalytic cycle.