Enhanced salt-tolerance of Bacillus subtilis glutaminase by fusing self-assembling amphipathic peptides at its N-terminus
Glutaminase (EC 3.5.1.2) can catalyze the deamidation of glutamine, which has been used to improve umami taste in oriental fermented foods. However, a high salt concentration is still a fundamental challenge for glutaminase application, especially in soy sauce production. To improve the salt toleran...
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| Format: | Article |
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Frontiers Media S.A.
2022-09-01
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| Series: | Frontiers in Bioengineering and Biotechnology |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fbioe.2022.996138/full |
| _version_ | 1797998874087915520 |
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| author | Song Liu Song Liu Song Liu Shengqi Rao Xiao Chen Xiao Chen Jianghua Li Jianghua Li |
| author_facet | Song Liu Song Liu Song Liu Shengqi Rao Xiao Chen Xiao Chen Jianghua Li Jianghua Li |
| author_sort | Song Liu |
| collection | DOAJ |
| description | Glutaminase (EC 3.5.1.2) can catalyze the deamidation of glutamine, which has been used to improve umami taste in oriental fermented foods. However, a high salt concentration is still a fundamental challenge for glutaminase application, especially in soy sauce production. To improve the salt tolerance of glutaminase, the self-assembling amphiphilic peptides EAK16 and ELK16 were fused to the N-terminus of a mutant (E3C/E55F/D213T) derived from Bacillus subtilis glutaminase, yielding the fusion enzymes EAK16-E3C/E55F/D213T and ELK16-E3C/E55F/D213T, respectively. As ELK16-E3C/E55F/D213T was expressed as insoluble active inclusion bodies, only the purified EAK16-E3C/E55F/D213T was subjected to further analyses. After the incubation with 18% (w/v) NaCl for 200 min, the residual activities of EAK16-E3C/E55F/D213T in a NaCl-free solution reached 43.6%, while E3C/E55F/D213T was completely inactivated. When the enzyme reaction was conducted in the presence of 20% NaCl, the relative activity of EAK16-E3C/E55F/D213T was 0.47-fold higher than that of E3C/E55F/D213T. As protein surface hydrophobicity and protein particle size analysis suggested, oligomerization may play an important role in the salt-tolerance enhancement of the fusions. Furthermore, EAK16-E3C/E55F/D213T achieved a 0.88-fold increase in the titer of glutamic acid in a model system of soy sauce fermentation compared to E3C/E55F/D213T. Therefore, the fusion with self-assembling amphiphilic peptides is an efficient strategy to improve the salt-tolerance of glutaminase. |
| first_indexed | 2024-04-11T10:55:40Z |
| format | Article |
| id | doaj.art-b8a5bcb748994d4aabdb2ecae6c35649 |
| institution | Directory Open Access Journal |
| issn | 2296-4185 |
| language | English |
| last_indexed | 2024-04-11T10:55:40Z |
| publishDate | 2022-09-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Bioengineering and Biotechnology |
| spelling | doaj.art-b8a5bcb748994d4aabdb2ecae6c356492022-12-22T04:28:46ZengFrontiers Media S.A.Frontiers in Bioengineering and Biotechnology2296-41852022-09-011010.3389/fbioe.2022.996138996138Enhanced salt-tolerance of Bacillus subtilis glutaminase by fusing self-assembling amphipathic peptides at its N-terminusSong Liu0Song Liu1Song Liu2Shengqi Rao3Xiao Chen4Xiao Chen5Jianghua Li6Jianghua Li7Science Center for Future Foods, Jiangnan University, Wuxi, Jiangsu, ChinaNational Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, Wuxi, Jiangsu, ChinaSchool of Biotechnology, Jiangnan University, Wuxi, Jiangsu, ChinaCollege of Food Science and Engineering, Yangzhou University, Yangzhou, Jiangsu, ChinaNational Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, Wuxi, Jiangsu, ChinaSchool of Biotechnology, Jiangnan University, Wuxi, Jiangsu, ChinaScience Center for Future Foods, Jiangnan University, Wuxi, Jiangsu, ChinaSchool of Biotechnology, Jiangnan University, Wuxi, Jiangsu, ChinaGlutaminase (EC 3.5.1.2) can catalyze the deamidation of glutamine, which has been used to improve umami taste in oriental fermented foods. However, a high salt concentration is still a fundamental challenge for glutaminase application, especially in soy sauce production. To improve the salt tolerance of glutaminase, the self-assembling amphiphilic peptides EAK16 and ELK16 were fused to the N-terminus of a mutant (E3C/E55F/D213T) derived from Bacillus subtilis glutaminase, yielding the fusion enzymes EAK16-E3C/E55F/D213T and ELK16-E3C/E55F/D213T, respectively. As ELK16-E3C/E55F/D213T was expressed as insoluble active inclusion bodies, only the purified EAK16-E3C/E55F/D213T was subjected to further analyses. After the incubation with 18% (w/v) NaCl for 200 min, the residual activities of EAK16-E3C/E55F/D213T in a NaCl-free solution reached 43.6%, while E3C/E55F/D213T was completely inactivated. When the enzyme reaction was conducted in the presence of 20% NaCl, the relative activity of EAK16-E3C/E55F/D213T was 0.47-fold higher than that of E3C/E55F/D213T. As protein surface hydrophobicity and protein particle size analysis suggested, oligomerization may play an important role in the salt-tolerance enhancement of the fusions. Furthermore, EAK16-E3C/E55F/D213T achieved a 0.88-fold increase in the titer of glutamic acid in a model system of soy sauce fermentation compared to E3C/E55F/D213T. Therefore, the fusion with self-assembling amphiphilic peptides is an efficient strategy to improve the salt-tolerance of glutaminase.https://www.frontiersin.org/articles/10.3389/fbioe.2022.996138/fullglutaminaseself-assembling amphipathic peptidestemperature stabilitysalt toleranceoligomerization |
| spellingShingle | Song Liu Song Liu Song Liu Shengqi Rao Xiao Chen Xiao Chen Jianghua Li Jianghua Li Enhanced salt-tolerance of Bacillus subtilis glutaminase by fusing self-assembling amphipathic peptides at its N-terminus Frontiers in Bioengineering and Biotechnology glutaminase self-assembling amphipathic peptides temperature stability salt tolerance oligomerization |
| title | Enhanced salt-tolerance of Bacillus subtilis glutaminase by fusing self-assembling amphipathic peptides at its N-terminus |
| title_full | Enhanced salt-tolerance of Bacillus subtilis glutaminase by fusing self-assembling amphipathic peptides at its N-terminus |
| title_fullStr | Enhanced salt-tolerance of Bacillus subtilis glutaminase by fusing self-assembling amphipathic peptides at its N-terminus |
| title_full_unstemmed | Enhanced salt-tolerance of Bacillus subtilis glutaminase by fusing self-assembling amphipathic peptides at its N-terminus |
| title_short | Enhanced salt-tolerance of Bacillus subtilis glutaminase by fusing self-assembling amphipathic peptides at its N-terminus |
| title_sort | enhanced salt tolerance of bacillus subtilis glutaminase by fusing self assembling amphipathic peptides at its n terminus |
| topic | glutaminase self-assembling amphipathic peptides temperature stability salt tolerance oligomerization |
| url | https://www.frontiersin.org/articles/10.3389/fbioe.2022.996138/full |
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