Figure 4

Figure 4

Structure validation and analysis of TRAF7 CC region. (A) Helical net diagram of one helical strand of TRAF7 CC trimer. One hendecad repeat is highlighted in the dashed box. The residues in the a/d positions of the heptad repeats and those in the a/d/x positions of the hendecad repeat are marked in yellow. (B) Combined ribbon and stick-ball models of TRAF7 CC to show the trimer interfaces. The main chains are shown as ribbons, and the side chains of hydrophobic and charged residues are shown as tick balls. (C) The surface charge distribution of TRAF7 CC. Many charged residues with large side chains are distributed on the trimer surface to protect the hydrophobic core. (D) Close-up view of L322 and L347 in the trimer interfaces. These hydrophobic residues are at the d positions, vital to form the trimeric core. (E) MALS measurement of TRAF7 CC molecular weights. A comparison with the wild-type TRAF7 CC (WT) shows lower molecular masses for both L322R and L347R mutants, indicating a weakening of the trimeric structure in solution. TRAF7 CC proteins (WT and mutant) were TrxA-tagged at the N-terminus for this experiment. The theoretical molecular weight of the WT trimer is 84.9 kDa.