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A mutation in the receiver domain of the Agrobacterium tumefaciens transcriptional regulator VirG increases its affinity for operator DNA
Author(s) -
Han Dong Cho,
Winans Stephen C.
Publication year - 1994
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.1994.tb00991.x
Subject(s) - biology , agrobacterium tumefaciens , cooperativity , microbiology and biotechnology , gene , genetics , transformation (genetics)
Summary We fused the wild‐type Agrobacterium tumefaciens virG gene and the constitutive virGN54D allele to the malE gene of Escherichia coli , and studied the binding of MBP—VirG fusions to the autoregulated virG promoter. MBP—VirGN54D protein bound this promoter with 10‐fold higher affinity than MBP—VirG, and bound to vir box I with eightfold higher affinity than to vir box III. Disruption of vir box III did not alter the affinity for vir box I, suggesting a lack of cooperativity between these sites. We provide evidence that protein bound at a single vir box may have a higher oligomeric state than non‐bound protein, and that a DNA distortion adjacent to vir box I may occur during activation.