An aromatic effector specificity mutant of the transcriptional regulator DmpR overcomes the growth constraints of Pseudomonas sp. strain CF600 on para-substituted methylphenols

• DOI: 10.1128/jb.176.24.7550-7557.1994
• Publication Date: 2016-11-07T21:37:39Z
• Authors: H Pavel; M Forsman; V Shingler
• Keywords: Catabolism; Transcription

The pVI150 catabolic plasmid of Pseudomonas sp. strain CF600 carries the dmp system, which comprises divergently transcribed dmpR gene and operon coding for enzymes required growth on (methyl)phenols. constitutively expressed DmpR transcriptional activator positively controls expression RpoN-dependent promoter in presence aromatic effector medium. However, magnitude response differs depending position methyl substituent ring. Experiments involving an elevated copy number system demonstrate that para-substituted methylphenols is limited by level enzymes. An specificity mutant DmpR, DmpR-E135K, responded to 4-ethylphenol, a noneffector wild-type protein, was isolated genetic selection. single point mutation results Glu-to-Lys change residue 135, also regulator with enhanced recognition methylphenols. DmpR-E135K mutation, when introduced into strain, confers utilization These experiments activation major factor limiting catabolism these compounds.