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Lrp, a major regulatory protein in Escherichia coli, bends DNA and can organize the assembly of a higher‐order nucleoprotein structure.
Author(s) -
Wang Q.,
Calvo J.M.
Publication year - 1993
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1993.tb05904.x
Subject(s) - biology , nucleoprotein , escherichia coli , escherichia coli proteins , dna , genetics , bacterial protein , order (exchange) , computational biology , microbiology and biotechnology , gene , finance , economics
Lrp (Leucine‐responsive regulatory protein) is a global regulatory protein that controls the expression of many operons in Escherichia coli. One of those operons, ilvIH, contains six Lrp binding sites located within a several hundred base pair region upstream of the promoter region. Analysis of the binding of Lrp to a set of circularly permuted DNA fragments from this region indicates that Lrp induces DNA bending. The results of DNase I footprinting experiments suggest that Lrp binding to this region facilitates the formation of a higher‐order nucleoprotein structure. To define more precisely the degree of bending associated with Lrp binding, one or two binding sites were separately cloned into a pBend vector and analyzed. Lrp induced a bend of approximately 52 degrees upon binding to a single binding site, and the angle of bending is increased to at least 135 degrees when Lrp binds to two adjacent sites. Lrp‐induced DNA bending, and a natural sequence‐directed bend that exists within ilvIH DNA, may be architectural elements that facilitate the assembly of a nucleoprotein complex.