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The bacterial pathogen, <i>Yersinia pestis</i>, has caused three historic pandemics and continues to cause small outbreaks worldwide. During infection, <i>Y. pestis</i> assembles a capsule-like protective coat of thin fibres of Caf1 subunits. This F1 capsular antigen has attracted much attention due to its clinical value in plague diagnostics and anti-plague vaccine development. Expression of F1 is tightly regulated by a transcriptional activator, Caf1R, of the AraC/XylS family, proteins notoriously prone to aggregation. Here, we have optimised the recombinant expression of soluble Caf1R. Expression from the native and synthetic codon-optimised <i>caf1R</i> cloned in three different expression plasmids was examined in a library of <i>E. coli</i> host strains. The functionality of His-tagged Caf1R was demonstrated in vivo, but insolubility was a problem with overproduction. High levels of soluble MBP-Caf1R were produced from codon optimised <i>caf1R</i>. Transcriptional-<i>lacZ</i> reporter fusions defined the P_M promoter and Caf1R binding site responsible for transcription of the <i>cafMA1</i> operon. Use of the identified Caf1R binding <i>caf</i> DNA sequence in an electrophoretic mobility shift assay (EMSA) confirmed correct folding and functionality of the Caf1R DNA-binding domain in recombinant MBP-Caf1R. Availability of functional recombinant Caf1R will be a valuable tool to elucidate control of expression of F1 and Caf1R-regulated pathophysiology of <i>Y. pestis</i>.