Insightful directed evolution of Escherichia coli quorum sensing promoter region of the lsrACDBFG operon: a tool for synthetic biology systems and protein expression.

Printer-friendly versionPrinter-friendly versionPDF versionPDF version
TitleInsightful directed evolution of Escherichia coli quorum sensing promoter region of the lsrACDBFG operon: a tool for synthetic biology systems and protein expression.
Publication TypeJournal Article
Year of Publication2016
AuthorsHauk, P, Stephens, K, Mckay, R, Virgile, CRyan, Ueda, H, Ostermeier, M, Ryu, K-S, Sintim, HO, Bentley, WE
JournalNucleic Acids Res
Volume44
Issue21
Pagination10515-10525
Date Published2016 Dec 01
ISSN1362-4962
Abstract

Quorum sensing (QS) regulates many natural phenotypes (e.q. virulence, biofilm formation, antibiotic resistance), and its components, when incorporated into synthetic genetic circuits, enable user-directed phenotypes. We created a library of Escherichia coli lsr operon promoters using error-prone PCR (ePCR) and selected for promoters that provided E. coli with higher tetracycline resistance over the native promoter when placed upstream of the tet(C) gene. Among the fourteen clones identified, we found several mutations in the binding sites of QS repressor, LsrR. Using site-directed mutagenesis we restored all p-lsrR-box sites to the native sequence in order to maintain LsrR repression of the promoter, preserving the other mutations for analysis. Two promoter variants, EP01rec and EP14rec, were discovered exhibiting enhanced protein expression. In turn, these variants retained their ability to exhibit the LsrR-mediated QS switching activity. Their sequences suggest regulatory linkage between CytR (CRP repressor) and LsrR. These promoters improve upon the native system and exhibit advantages over synthetic QS promoters previously reported. Incorporation of these promoters will facilitate future applications of QS-regulation in synthetic biology and metabolic engineering.

DOI10.1093/nar/gkw981
Alternate JournalNucleic Acids Res.
PubMed ID27915294
PubMed Central IDPMC5137460