Unexpectedly high thermostability of an NADP-dependent malic enzyme from a psychrophilic bacterium, Shewanella livingstonensis Ac10

• Published in: Journal of bioscience and bioengineering Vol. 132; no. 5; pp. 445 - 450
• Main Authors: Luo, Gonglinfeng, Fujii, Sotaro, Koda, Takumi, Tajima, Takahisa, Sambongi, Yoshihiro, Hida, Akiko, Kato, Junichi
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.2021
• Subjects: Functional temperature range; NADP-dependent malic enzyme; Psychrophilic enzyme; Shewanella livingstonensis; Thermostability; Thermostability; Shewanella livingstonensis; Functional temperature range; Psychrophilic enzyme; NADP-dependent malic enzyme
• ISSN: 1389-1723; 1347-4421
• DOI: 10.1016/j.jbiosc.2021.07.005

Psychrophilic enzymes are generally active at low temperatures, and their functions have attracted much interest in food processing, biochemical research, and chemical industry. However, their activities are usually lost above their growth temperature because of their flexible and unstable structure. Here, we unexpectedly found that a homodimeric NADP-dependent malic enzyme from a psychrophilic bacterium, Shewanella livingstonensis Ac10 (SL-ME) showed sufficient activity with 60°C treatment, similar to its counterpart from mesophilic Escherichia coli (MaeB). Consistently, SL-ME and MaeB irreversibly denatured at 71.9°C and 64.5°C, respectively. Therefore, SL-ME shows robust catalytic activity, which appears to be advantageous for its application in the bioconversion of NADP to NADPH, an essential ingredient for membrane phospholipid synthesis.