Functional conformational changes of endo‐1,4‐xylanase II from Trichoderma reesei: A molecular dynamics study

Recent crystallographic studies have revealed a range of structural changes in the three‐dimensional structure of endo‐1,4‐xylanase (XYNII) from Trichoderma reesei. The observed conformational changes can be described as snapshots of an open‐close movement of the active site of XYNII. These structures were further analyzed in this study. In addition, a total of four 1 ns molecular dynamics (MD) simulations were performed representing different states of the enzyme. A comparison of the global and local changes found in the X‐ray structures and the MD runs suggested that the simulations reproduced a similar kind of active site opening and closing as predicted by the crystal structures. The open‐close movement was characterized by the use of distance difference matrixes and the Hingefind program (Wriggers and Schulten, Proteins 29:1–14, 1997) to be a ‘hinge‐bending’ motion involving two large rigidly‐moving regions and an extended hinge. This conformational feature is probably inherent to this molecular architecture and probably plays a role in the function of XYNII. Proteins 31:434–444, 1998. © 1998 Wiley‐Liss, Inc.

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