| Autor: |
Tatsuya Osamura, Mitsuyoshi Okuda, Atsushi Yamaguchi, Kazumasa Ohtake, Kensaku Sakamoto, Yasushi Takimura |
| Jazyk: |
angličtina |
| Rok vydání: |
2019 |
| Předmět: |
|
| Zdroj: |
Biochemistry and Biophysics Reports, Vol 17, Iss , Pp 93-96 (2019) |
| Druh dokumentu: |
article |
| ISSN: |
2405-5808 |
| DOI: |
10.1016/j.bbrep.2018.12.001 |
| Popis: |
In the present study, we attempted to control the pH profile of the catalytic activity of the industrially relevant alkaline protease KP-43, by incorporating 3-nitro-l-tyrosine and 3-chloro-l-tyrosine at and near the catalytic site. Thirty KP-43 variants containing these non-natural amino acids at the specific positions were synthesized in Escherichia coli host cells with expanded genetic codes. The variant with 3-nitrotyrosine at position 205, near the substrate binding site, retained its catalytic activity at the neutral pH and showed a 60% activity reduction at pH 10.5. This reduction in the alkaline domain is desirable for enhancing the stability of the enzyme in the liquid laundary detergent, whereas the wild-type molecule showed a 20% increase in response to the same pH shift. The engineered pH dependency of the activity of the variant was ascribed partly to a lowered substrate affinity under the alkaline conditions, in which the incorporated 3-nitrotyrosine was probably charged negatively due to the phenolic pKa lower than that of tyrosine. Keywords: Detergent enzyme, Alkaline protease, Nitrotyrosine, Chlorotyrosine, Protein engneerings |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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