Allostery in the LacI/GalR family: variations on a theme.
The lactose repressor protein (LacI) was among the very first genetic regulatory proteins discovered, and more than 1000 members of the bacterial LacI/GalR family are now identified. LacI has been the prototype for understanding how transcription is controlled using small metabolites to modulate protein association with specific DNA sites. This understanding has been greatly expanded by the study of other LacI/GalR homologues. A general picture emerges in which the conserved fold provides a scaffold for multiple types of interactions - including oligomerization, small molecule binding, and protein-protein binding - that in turn influence target DNA binding and thereby regulate mRNA production. Although many different functions have evolved from this basic scaffold, each homologue retains functional flexibility: For the same protein, different small molecules can have disparate impact on DNA binding and hence transcriptional outcome. In turn, binding to alternative DNA sequences may impact the degree of allosteric response. Thus, this family exhibits a symphony of variations by which transcriptional control is achieved.
Swint-Kruse
Liskin
L
Department of Biochemistry and Molecular Biology, The University of Kansas Medical Center, Kansas City, 66160, United States. lswint-kruse@kumc.edu
Matthews
Kathleen S
KS
D000494:Allosteric Regulation / Q000502:physiology*; D018407:Bacterial Physiological Phenomena; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D004926:Escherichia coli / Q000502:physiology*; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000378:metabolism*; D056968:Lac Repressors; D012097:Repressor Proteins / Q000737:chemistry / Q000378:metabolism*
D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; C050993:Galactose repressor proteins; D056968:Lac Repressors; C539064:LacI protein, E coli; D012097:Repressor Proteins