Analysis of novel zinc-binding proteins in the cell wall of <i>Corynebacterium diphtheriae</i>

Zinc is a critical nutrient required by many bacterial pathogens. While the function of multiple zinc importer systems has been previously characterized in <i>Corynebacterium diphtheriae</i>, the transporter encoded by the <i>znu</i> gene cluster includes components not found in other metal transport systems. In this report, we examined the roles of three components of the <i>znu</i> gene cluster, ZnuE, ZnuF, and ZnuG, and show that these proteins all possess a putative zinc-binding domain and have varying effects on growth in zinc-limited medium. Additionally, ZnuF uses a novel mechanism for cell wall localization. This study further expands our understanding of <i>C. diphtheriae</i> zinc import and points to a potentially novel mechanism for the localization of cell wall proteins.