FIGURE 2.

Relative activities of the arginine mutants in comparison to WT LTC₄S. A, relative activities of the arginine mutants in comparison to WT LTC₄S are shown with S.D. The enzyme activities of the mutant enzymes with LTA₄ and LTA₄-Me were normalized to the enzyme activities of the WT LTC₄S with LTA₄ and LTA₄-Me, respectively. The open and the closed bars depict the relative enzyme activities measured using LTA₄ (F) and LTA₄-Me (M), respectively. B, the arginine residues mutated in this work are shown by stick models. The ribbon model with green is a monomer in the LTC₄S trimer, and the other two are shown in gray. The translucent stick model with yellow carbons represents the putative LTA₄ binding model, and the alkyl chain of the dodecyl maltoside used for the modeling of the LTA₄ is shown by the stick model with orange carbons. The conformation of the side chain of Arg-31 is the one most commonly observed (55). The side chain did not have a uniform conformation in the crystal structure. Therefore, the side chain of Arg-31 modeled was represented by the translucent stick model.