Characterization of a temperature-sensitive DNA ligase from Escherichia coli

Lavesa-Curto, Manuel, Sayer, Heather, Bullard, Desmond, MacDonald, Andrew, Wilkinson, Adam, Smith, Andrew, Bowater, Laura, Hemmings, Andrew ORCID: and Bowater, Richard P. ORCID: (2004) Characterization of a temperature-sensitive DNA ligase from Escherichia coli. Microbiology, 150. pp. 4171-4180. ISSN 1465-2080

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DNA ligases are essential enzymes in cells due to their ability to join DNA strand breaks formed during DNA replication. Several temperature-sensitive mutant strains of Escherichia coli, including strain GR501, have been described which can be complemented by functional DNA ligases. Here, it is shown that the ligA251 mutation in E. coli GR501 strain is a cytosine to thymine transition at base 43, which results in a substitution of leucine by phenylalanine at residue 15. The protein product of this gene (LigA251) is accumulated to a similar level at permissive and non-permissive temperatures. Compared to wild-type LigA, at 20 °C purified LigA251 has 20-fold lower ligation activity in vitro, and its activity is reduced further at 42 °C, resulting in 60-fold lower ligation activity than wild-type LigA. It is proposed that the mutation in LigA251 affects the structure of the N-terminal region of LigA. The resulting decrease in DNA ligase activity at the non-permissive temperature is likely to occur as the result of a conformational change that reduces the rate of adenylation of the ligase.

Item Type: Article
Faculty \ School: Faculty of Science > School of Biological Sciences
UEA Research Groups: Faculty of Science > Research Groups > Molecular Microbiology
Faculty of Science > Research Groups > Biophysical Chemistry (former - to 2017)
Faculty of Science > Research Groups > Plant Sciences
Faculty of Science > Research Groups > Chemistry of Life Processes
Faculty of Science > Research Centres > Centre for Molecular and Structural Biochemistry
Depositing User: EPrints Services
Date Deposited: 01 Oct 2010 13:37
Last Modified: 15 Dec 2022 12:30
DOI: 10.1099/mic.0.27287-0


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