Generalized squared order parameters (S2) along sequence for amide NH bonds in peptide planes. MD-derived (red circles) and NMR relaxation (green diamonds) S2 are compared for TEM-1 (A) and PSE-4 (D). Free (red circles) and substrate-bound (blue squares) S2 are compared for TEM-1 (B) and PSE-4 (E). Difference between MD and NMR S2 for the free form (blue squares), and for the free and bound forms (red circles) are given for TEM-1 (C) and PSE-4 (F). Catalytic residues (S70, K73, S130, E166, and K/R234) are indicated with gray lines, the Ω loop with a light gray box. Indicated above panels are TEM-1 and PSE-4 sequences: α-helices are white boxes; β-strands gray boxes; the Ω loop is in light gray; a vertical bar in H2 indicates the bend between H2A and H2B. NMR data were taken from (18) (TEM-1) and (19) (PSE-4).