Thermal expansion of hen egg-white lysozyme. Comparison of the 1.9 A resolution structures of the tetragonal form of the enzyme at 100 K and 298 K.

摘要: The average structural and dynamic properties of tetragonal hen egg-white lysozyme have been compared, in structures refined at 1.9 A resolution, using data collected 100 K 298 K. molecule expands by 1.8% over this temperature range with the expansion occurring primarily its small sub-atomic-sized spaces an anisotropic manner. Hen consists two domains: domain 1 (residues 40 to 88) is composed beta-sheet observed expand only 0.3%; 2 39 89 129) chiefly alpha-helix 2.2%. This consistent previous observations that proteins more than do those beta-sheet. largest movement undergone domains structure move further apart as raised. motion not a cleft opening but rather tilt 2.3 degrees away from 2. Within individual loop T1 2, consisting residues 17 23. moves opposite direction rest Average factors for room-temperature low-temperature are 15.2 A2 8.1 A2, respectively, when all protein atoms considered, while these values 14.0 7.8 main-chain (N, C alpha, C) taken into account. An examination averaged B-factor per residue shows involved intermolecular protein-protein contacts, symmetry-related molecules, somewhat lower B-factors undergo smaller changes lowered.