Comparative Analysis of Room Temperature Structures Determined by Macromolecular and Serial Crystallography

Abstract

Temperature directly influences the function and structure of proteins. Crystal structures determined at room temperature offer more biologically relevant structural information regarding flexibility, rigidity, and thermal motion than those determined by conventional cryocrystallography. Crystal structures can be determined at room temperature using conventional macromolecular crystallography (MX) or serial crystallography (SX) techniques. Among these, MX may theoretically be affected by radiation damage or X-ray heating, potentially resulting in differences between the room temperature structures determined by MX and SX, but this has not been fully elucidated. In this study, the room temperature structure of xylanase GH11 from Thermoanaerobacterium saccharolyticum was determined by MX (RT-TsaGH11-MX). The RT-TsaGH11-MX exhibited both the open and closed conformations of the substrate-binding cleft within the β-sandwich fold. The RT-TsaGH11-MX showed distinct structural changes and molecular flexibility when compared with the RT-TsaGH11 determined via serial synchrotron crystallography. The notable molecular conformation and flexibility of the RT-TsaGH11-MX may be induced by radiation damage and X-ray heating. These findings will broaden our understanding of the potential limitations of room temperature structures determined by MX.

Recognition of a Single β-D-Xylopyranose Molecule by Xylanase GH11 from Thermoanaerobacterium saccharolyticum

“…The GH11 from T. saccharolyticum (TsaGH11) exhibits a highly efficient K cat value of 34,015 s −1 at pH 5.0 and 70 • C toward beechwood xylan, thus suggesting its attractive potential for industrial applications [29]. To gain a deeper understanding of its enzymatic activity and molecular mechanisms, the room-temperature structure of TsaGH11 was determined using serial synchrotron crystallography and macromolecular crystallography [29][30][31]. In addition, the crystal structure of TsaGH11 at a basic pH was determined, which revealed subtle pH-induced structural changes of the substrate-binding cleft [32].…”