Biochemical characteristics of wild-type and mutant Mal-TIR domains.

<p>(<b>A</b>) Structural comparison between wild-type and mutant Mal-TIR domains. Crystal structures of the wild-type (cyan), D96N (magenta) and S180L (yellow) mutants of the Mal-TIR domain are shown. The residues Asp96 and Ser180 in the wild type as well as Asn96 in D96N and Leu180 in S180L are labeled. Nitrogen and oxygen atoms in the side chains are colored blue and red, respectively. (<b>B,D</b>) Electrostatic surfaces of wild type and the D96N mutant or the S180L mutant. Surfaces are colored by electrostatic potential ranging from red (−10 k_bT/e_c) to blue (+10 k_bT/e_c), where k_b is the Boltzmann constant, T is temperature and e_c is the electron charge. The electrostatic potentials were calculated by solving the Poisson-Boltzmann equation with APBS plugin of PyMol program (DeLano Scientific LLC). (<b>C,E</b>) The molecular surfaces of wild-type (left) and the D96N mutant (right) or the S180L mutant of the Mal-TIR domains. Carbon, nitrogen, oxygen and sulfur atoms are colored yellow, blue, red and orange, respectively. (<b>F</b>) GST pull-down assay for the interaction of wild-type Mal-TIR and mutants with TLR4-TIR and MyD88-TIR.