Kamo Masayuki, Inouye Kuniyo, Nagata Koji, Tanokura Masaru
Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
Acta Crystallogr D Biol Crystallogr. 2005 Jun;61(Pt 6):710-2. doi: 10.1107/S0907444905006864. Epub 2005 May 26.
The activity of thermolysin (EC 3.4.24.27) is greatly enhanced by high concentrations of neutral salts. For instance, 4 M NaCl enhances the activity 13-15-fold [Holmquist & Vallee (1976), Biochemistry, 15, 101-107; Inouye (1992), J. Biochem. (Tokyo), 112, 335-340]. To clarify the structural basis of the activation of thermolysin by high concentrations of NaCl, we have developed a new method to introduce 4 M NaCl into the P6(1)22 crystal of thermolysin originally grown without NaCl. The crystal obtained by this method diffracted X-rays to 2.43 A. No unit-cell parameter change was observed except the length of the c axis, which was elongated by 9.6% by the introduction of 4 M NaCl.
