Purification, crystallization, and X-ray crystallographic analysis terephthalic acid binding protein from Ideonella sakaiensis

초록

Periplasmic terephthalic acid binding protein (TBP) from Ideonella sakaiensis (IsTBP) is a periplasmic protein that imports TPA to the cytoplasm interacting with the TTT-transport system. In this study, we overexpressed IsTBP and purified the protein to homogeneity by Ni-NTA affinity and size-exclusion chromatography. The IsTBP protein was crystallized using hanging-drop vapor-diffusion method in the presence of 20% PEG3350 and 0.2 M Ammonium iodide at 20°C. X-ray diffraction data were collected to a maximum resolution of 1.02 Å. The IsTBP crystals belonged to the space group P21 with unit cell parameters a = 46.2 Å, b = 54.1 Å, c = 50.6 Å. With one molecule of IsTBP per asymmetric unit, the crystal volume per unit of protein mass was 2.32 Å3 Da–1, which corresponds to a solvent content was approximately 47.00%.