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PMID: 2826131 Published · ppublish English Journal Article Research Support, Non-U.S. Gov't

The interaction of the recognition helix of lac repressor with lac operator.

The EMBO journal ·Vol. 6 ·No. 10 ·1987-10-00 ·Pages 3145-53

Lehming N, Sartorius J, Niemöller M, Genenger G, v Wilcken-Bergmann B, Müller-Hill B

Abstract

We have constructed a system which allows systematic testing of repressor--operator interactions. The system consists of two plasmids. One of them carries a lac operon in which lac operator has been replaced by a unique restriction site into which synthetic operators can be cloned. The other plasmid carries the gene coding for the repressor, in our case a semisynthetic lacI gene of which parts can be exchanged in a cassette-like manner. A galE host allows us to select for mutants which express repressors with altered specificities. Here we report the change of specificity in the lac system by changing residues 1 and 2 of the recognition helix of lac repressor. The specificity changes are brought about cooperatively by the change of both residues. Exchanges of just one residue broaden the specificity. Our results hint that the recognition helix of lac repressor may possibly have the opposite orientation to those in Lambda cro protein or 434 CI repressor.

MeSH Terms
Amino Acid Sequence Base Sequence Cloning, Molecular DNA Restriction Enzymes Escherichia coli/genetics Genetic Variation Lac Operon Molecular Sequence Data Plasmids Repressor Proteins/genetics,metabolism Transcription Factors/metabolism
Chemicals
Repressor Proteins Transcription Factors DNA Restriction Enzymes
Authors & Affiliations
6 authors, click to expand affiliations / ORCID
Lehming N
Institut für Genetik der Universität zu Köln, FRG.
Sartorius J
Niemöller M
Genenger G
v Wilcken-Bergmann B
Müller-Hill B
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Article Info
Journal
The EMBO journal
Abbr.
EMBO J
ISSN
0261-4189
Published
1987-10-00
Pages
3145-53
Language
English
Region
England
NLM ID
8208664
PMCID
PMC553756
Subset
IM
Databases
GENBANK
X06035
External Links
PubMed source PMC Full Text View journal details
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