Pneumococcal Transformation: ComW is a DNA Binding Protein that Stimulates Competence Gene Transcription

Natural genetic transformation via horizontal gene transfer enables rapid adaptation to dynamic environments and contributes to antibiotic resistance and vaccine evasion in bacteria. Most transformable bacteria require entry into a competent state, in which the express genes required for DNA uptake and recombination. The growth phases, environmental cues, and molecular signals that promote competence differ from one species to the another, but ultimately lead to expression of specific transcriptional regulators to target competence genes for expression. Competent pneumococci rely on expression of the alternative sigma factor, SigX, and a novel sigma factor activator, ComW, for expression of transformation genes. This thesis explores the function of ComW. In the absence of a predictable function, creation of an ab initio model of ComW's 3D structure led to the reliable purification and characterization of a soluble ComW variant, discovery and analysis of its DNA-binding activity, and functional assays for affects on SigX-mediated transcription during in vitro transcription.