FIGURE 1.

Fragments of soluble elastin exert NMR spectral effects around the periphery of the active site cleft of inactivated MMP-12. Eln-20 was added at 1.5-fold molar excess over E219A-inactivated MMP-12 (0.3 mm). The 10% of amide TROSY peaks most broadened by the addition are marked with triangles in a and light green coloring of the NMR structure (49) in b. The backbone ribbon and transparent molecular surface in standard orientation in b displays unprimed subsites at left and primed subsites at right. Radial changes in chemical shift of amide NMR peaks in a, Δω_HN = [Δω_H² + (Δω_N/5)²]^1/2, were measured at 800 MHz, 26 °C, and pH 6.6. Residues with Eln-20-induced Δω_HN ≥ 0.04 ppm are red and those with 0.04 > Δω_HN ≥ 0.02 ppm are orange in b. β-Strands are labeled with Roman numerals, and helices are labeled with letters a and b.