Response to Comment on "Crystal structures of translocator protein (TSPO) and mutant mimic of a human polymorphism"

Abstract

Wang comments that the diffraction data for the structure of the A139T mutant of translocator protein TSPO from Rhodobacter sphaeroides should be used to 1.65 instead of 1.8 angstroms and that the density interpreted as porphyrin and monoolein is better fitted as polyethylene glycol. Although different practices of data processing exist, in this case they do not substantially influence the final map. Additional data are presented supporting the fit of a porphyrin and monooleins.

Fig. 1. Structure of RsTSPO-A139Tobtained in pentaerythritol ethoxylate 15/04 is very similar to that obtained in PEG 400

(A) Structure of RsTSPO-A139T crystallized in PEG 400 (cyan) and pentaerythritol ethoxylate 15/04 (light cyan) show identical features of the porphyrin-like molecules (magenta and light magenta spheres) and most monooleins (orange and yellow sticks). A PEG molecule (green) could be fitted into the 1.8 Å structure but not in the 2.4 Å structure. One asymmetric unit containing three monomers is shown. (B) Structure of pentaerythritol ethoxylate 15/04. (C) Ring-shaped density (2F_obs – F_calc) and the fitting of a porphyrin-like molecule in the 2.4-Å structure obtained with pentaerythritol ethoxylate 15/04.