Fig. 1: Structure and dynamics of the HtrA2-PDZ domain in solution.
a Scheme of the used constructs indicating the domain structure of mature human HtrA2. Residues of the catalytic triad and important regulatory loops are labeled. b Crystal structure of the proteolytically active HtrA2 trimer (PDB-ID: 5M3N) focusing on the protease-PDZ-domain interface of a single subunit (complete trimer: Supplementary Fig. 1). Different domains (PDZ domain: green; protease domain: blue) and the catalytic triad composed of H198, D228, and S306 are indicated (gold). c 2D [15N, 1H]-NMR spectrum of the [U-15N,13C]-HtrA2-PDZ domain. The sequence-specific resonance assignment based on triple-resonance experiments is shown. d Secondary structure elements of the HtrA2-PDZ domain in solution (green). The secondary structure elements of the HtrA2-PDZ domain within the full-length crystal structure (PDB-ID: 5M3N) are indicated in gray. e Generalized order parameter (S2) reporting on sub-nanosecond motions plotted on the HtrA2-PDZ structure. The backbone amide moieties of the HtrA2-PDZ domain are shown as spheres and the S2 values are indicated by the yellow-to-blue gradient. f Analysis of 15N-backbone relaxation data with the Lipari–Szabo model-free approach. The generalized order parameter S2 reports on pico- to nanosecond motions, the chemical exchange contributions Rex indicating micro- to millisecond motions, and the rotational correlation time τc. Broken line represents the average value of 8.2 ns. Error bars indicate the standard fitting error obtained from the nonlinear least-squares minimization. g The amide moieties of the HtrA2-PDZ domain are shown as spheres. The calculated Rex is indicated by the yellow-to-red gradient. Source data are provided as a Source Data File.
