Biophysical analysis of MarR family transcription factors from Streptomyces coelicolor

Streptomycetes represent a rich source of potentially useful therapeutics. However, in a laboratory environment, a large proportion of their secondary metabolite gene clusters remain silent, and thus their full metabolic potential is not realised. One way to unlock these so-called "cryptic" clusters may be to manipulate specific regulatory proteins. But, the vast majority of these regulators are uncharacterized, making it difficult to do this in a rational way. The MarR family of regulatory proteins (MFRs) represents an important group of transcriptional regulators. Named after the first to be characterized in Escherichia coli, the multiple antibiotic resistance repressor (MarR), the members of this family are involved in a number of biological processes which include antibiotic resistance, virulence, oxidative stress responses and pathogenesis and are therefore of significant clinical interest. There are 42 of these MFRs present in the genome of Streptomyces coelicolor, a prolific producer of secondary metabolites, the majority of which are uncharacterized. In this work, the crystal structures of three of these MFRs from Streptomyces coelicolor, Sco3914, Sco4122 and Sco5413, have been determined using anomalous dispersion methods. The structure of Sco5413 was determined to 1.25 Å resolution, the highest resolution for an MFR at this point. Genetic and biophysical analyses of these transcription factors have also been performed and the DNA footprints of Sco3914 and Sco4122 have been defined. Disruption mutants for each of the genes have been created and phenotypic analysis revealed a distinct phenotype for Sco5413. The structures do not reveal a ligand for any of the structures, but comparisons with other MFR structures provide some evidence towards a conserved ligand binding site amongst MFRs.

Name dc:type.qualificationname

phd

Level dc:type.qualificationlevel

doctoral

Grantor dc:publisher.institution

University of East Anglia

Year dc:date.issued

2012

Author dc:creator

• Holley, Tracey

Language dc:language

en