Determining the gene regulatory network of an organism is fundamental to achieving a global understanding of cell behavior. In general, studies of transcription regulation are limited to the annotated transcription factors, not considering other non-canonical regulators. Here we describe the first systematic analysis of the DNA-interactome of a bacterium with a minimal proteome (Mycoplasma pneumoniae). We first determined by DNA affinity chromatography and intact chromatin isolation all potential DNA binding proteins. We then mapped the DNA binding of these factors by ChIP-seq, as well as their functionality by gain- and loss-of-function experiments, by transcriptomics and proteomics. This identified new DNA binding proteins and novel regulators with moonlighting properties like proteases and metabolic enzymes and allowed to reconstruct the gene regulatory network.