These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Substitution of Asp189 residue alters the activity and thermostability of Geobacillus sp. NTU 03 lipase.
    Author: Shih TW, Pan TM.
    Journal: Biotechnol Lett; 2011 Sep; 33(9):1841-6. PubMed ID: 21544610.
    Abstract:
    Error-prone PCR was used to create more thermoactive and/or thermostable variants of thermoalkalophilic lipases. A variant of the α6 helix (lid domain), with an 189E to V substitution at residue 189, lost its thermostability but exhibited higher activity than that of its wild-type predecessor (r03Lip). Site-saturation mutagenesis was used to explore the sequence-function relationship. Five other mutants also lost thermostability (20-40%) but exhibited enhanced thermoactivity (6.3-79-fold). The mutant E189I showed the highest activity retaining 50% activity after maintaining it at 65 °C for 24 h. In comparison to r03Lip, the mutant E189I had a higher affinity for p-nitrophenyl palmitate and p-nitrophenyl stearate (61 and 56% decreased Km) and catalytic efficiency (42-fold and 18-fold increased kcat/Km). The mutant lipase retained its tolerance to n-hexane, but had an improved transesterification activity. The results suggest that residue Glu189 plays a significant role in the thermostability and activity of this thermoalkalophilic lipase.
    [Abstract] [Full Text] [Related] [New Search]