Single-point amino acid substitutions at the 119th residue of thermolysin and their pressure-induced activation

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• 作者：Kunugi ; Shigeru ; Fujiwara ; Satoshi ; Kidokoro ; Shun-ichi ; et. al.
• 关键词：Thermolysin ; Pressure ; Activation ; Amino acid substitution ; Protein stability ; Fua- ; N-(3-[2-furyl]acryloyl)- ; TLN ; thermolysin ; mut-TLNs ; mutated thermolysins ; HEPES ; 2-[4-(2-hydroxyethyl)-1-piperazinyl]ethanesulfonic acid
• 刊名：FEBS Letters
• 出版年：1999
• 出版时间：December 3, 1999
• 年：1999
• 卷：462
• 期：3
• 页码：231-235
• 全文大小：145 K

文摘

The effect of amino acid substitution at the 119th site of thermolysin (TLN) on the pressure activation behavior of this enzyme was studied for four mutants at pressures <300 MPa. For Q119Q, Q119N and Q119R, the highest activation was observed to be over 30 times that at atmospheric pressure and the activation volumes (ΔV^&Dagger;) were about &minus;75 ml/mol. However, we obtained only 10 times higher activation for Q119E and Q119D (ΔV^‡s/glyphs/BQ1.GIF>&minus;60 ml/mol). The intrinsic fluorescence of TLN changed at pressures >300 MPa, and the latter two mutants showed a smaller ΔG<sub>appsub> and ΔV<sub>appsub> of transition than the wild type. These results are discussed with respect to the hydration change in the enzyme protein around the substituted region.