Premium
Surface plasmon resonance studies of wild‐type and AV77 tryptophan repressor resolve ambiguities in super‐repressor activity
Author(s) -
Finucane Michael D.,
Jardetzky Oleg
Publication year - 2003
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1110/ps.0305703
Subject(s) - repressor , surface plasmon resonance , tryptophan , in vitro , chemistry , biophysics , resonance (particle physics) , dna , in vivo , biology , biochemistry , physics , genetics , gene , gene expression , atomic physics , quantum mechanics , amino acid , nanoparticle
The interactions of wild‐type (WT) and AV77 tryptophan repressor (TR) with several operators have been studied using surface plasmon resonance. The use of this real‐time method has been able to settle several outstanding issues in the field, in a way that has heretofore not been possible. We resolve the issue of the super‐repressor status of the AV77 aporepressor and find that in contrast to early studies, which found no significant difference in the binding constants in vitro to those of the WT, that there is indeed a clear difference in the binding constant that can simply account for the phenotype. Accordingly, there is no need for alternative proposals invoking complex equilibria with in vivo components not found in the in vitro experiments. In addition, we find that the AV77 holorepressor–DNA complex is much more stable than the equivalent WT complex, which has not been apparent from either in vitro or equilibrium binding experiments.