L-Glutamate Enhances the Expression of Thermus Maltogenic Amylase in Escherichia coli

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• 作者：Hyung-Moo Jung ; Kwan-Hwa Park ; Sang-Yong Kim ; and Jung-Kul Lee
• 刊名：Biotechnology Progress
• 出版年：2004
• 出版时间：February 2004
• 年：2004
• 卷：20
• 期：1
• 页码：26 - 31
• 全文大小：111K
• 年卷期：v.20,no.1(February 2004)
• ISSN：1520-6033

文摘

Escherichia coli BL21 (DE3) transformed with a thermostable Thermus maltogenicamylase (ThMA), isolated from a Gram-negative bacterium Thermus strain IM6501,grew well and efficiently produced ThMA in a complex medium but not in a chemicallydefined medium (DM). By supplementing L-glutamate to DM medium, both the specificgrowth rate and ThMA expression significantly increased. Alterations in the cellularresponses of recombinant E. coli to L-glutamate were analyzed at the protein level bytwo-dimensional gel electrophoresis and mass spectrometry. The ppGpp synthase(RelA) was significantly reduced in cells grown with L-glutamate and was consistentwith the low level of ppGpp, an indicator of stringent response. On the other hand,protein chain elongation factor (EF-Tu) and manganese-containing superoxide dismutase (MnSOD), which protects cells against oxidative damage, was significantlyelevated by L-glutamate supplementation. These results indicate that L-glutamateenhances ThMA expression and increases the E. coli growth rate not only byovercoming the stringent response but also by increasing the synthesis of EF-Tu andMnSOD.