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Updated: Jun 20, 2026

Growth-based Determination and Biochemical Confirmation of Genetic Requirements for Protein Degradation in Saccharomyces cerevisiae
Published on: February 16, 2015
Residue Tyr224 is critical for the thermostability of Geobacillus sp. RD-2 lipase
1State Key Laboratory of Microbial Technology, Shandong University, 27 Shanda Nan Rd., 250100, Jinan, People's Republic of China.
Abstract:
A thermophilic lipase (lipGRD) from Geobacillus sp. RD-2, isolated from a hot spring in Yunnan, China, was cloned and over-expressed in Escherichia coli. The function of the conserved residue, Tyr224, near the presumed temperature switch site was analyzed by site-directed saturation mutagenesis. The activity of the wild type lipGRD was optimal at 55 degrees C and pH 7.5, but that from mutant Y224C was optimally active at 35 degrees C, whereas Y224P lipase was optimally active at 65 degrees C. Furthermore, the latter lipase retained 60% of its activity after incubation at 65 degrees C for 5 h. The conserved residue Tyr224, which is close to the lid helix, is the key amino acid residue determining the thermostability of the thermostable lipase.
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