FIGURE 4.

Structural dynamics of the SH2 tandem in different constructs. The conformational variability of the tandem is represented as a probability density in two dimensions, namely the r.m.s.d. relative to the apo (x axis) or ITAM-bound (y axis) structures determined by crystallography. The location of the actual crystal structures in this representation is indicated by green circles as follows: ITAM-bound ZAP-70 (9) in a, b, e, and f; ITAM-bound Syk (10) in c and d; apo ZAP-70 (6) in a; and kinase-bound ZAP-70 (11) in g. In panel c, additional experimental structures of the corresponding SH2 tandem from the same crystal are indicated. Green dashed lines indicate the approximate direction of motion between apo and ITAM-bound states of ZAP-70, as observed in the simulations of the tSH2^ZAPApo (a) and tSH2^ZAPΔITAM (b) constructs. Correlation coefficients between selected probability density distributions from this figure are shown in Table 1. w.r.t., with respect to.