Isolation of the amino-terminal fragment of lactose repressor necessary for DNA binding
- 8 March 1977
- journal article
- research article
- Published by American Chemical Society (ACS) in Biochemistry
- Vol. 16 (5) , 938-943
- https://doi.org/10.1021/bi00624a020
Abstract
The lac repressor [of Escherichia coli] can be dissected by trypsin into a homogeneous tetrameric core (accounting for residues 60-347), carrying inducer binding activity, and the monomeric amino-terminal peptides (headpieces) accounting for residues 1-59 and 1-51, respectively. This restriction of the action of trypsin on lac repressor is obtained in 1 M Tris-HCl (pH 7.5)-30% in glycerol at 25.degree. C, since only the peptide bonds at lysine-59 and to a lesser extent at arginine-51 are cleaved under these conditions. The headpieces can be purified by gel filtration. They have ordered secondary structure as revealed by circular dichroism studies. The monomeric headpieces show the relatively weak binding to nonoperator DNA but not the highly specific and strong binding to operator DNA typical for tetrameric lac repressor.This publication has 5 references indexed in Scilit:
- Isolation of a set of hybrid lac repressors made in vitro between normal lac repressor and its homogeneous tryptic core.Proceedings of the National Academy of Sciences, 1976
- Limited proteolytic digestion of lac repressor by trypsin. Chemical nature of the resulting trypsin-resistant core.Journal of Biological Chemistry, 1976
- DNA binding of the lac repressorJournal of Molecular Biology, 1968
- Mutants that make more lac repressor.Proceedings of the National Academy of Sciences, 1968
- The action of trypsin on polylysineBiochemical Journal, 1953