The emergence of multi-drug resistant bacterial pathogens is generating enormous public health concern, and highlights an urgent need for new, alternative agents for treating multi-drug-resistant pathogens. The gene products essential for bacterial growth in vitro and survival during infection constitute an initial set of protein targets for the development of antibacterial agents. In this study, we employed regulated gene expression approaches and demonstrated that a putative glycoprotease (Gcp) is required for staphylococcal growth in the culture. We found that Staphylococcus aureus becomes more sensitive to the Zn(2+) ion under the downregulation of Gcp expression in vitro. Bioinformatic analyses demonstrated that Gcp is conserved in many Gram-positive pathogens and exists in a variety of Gram-negative pathogens. Our results indicate that Gcp is a potential novel target for the development of antimicrobials against S. aureus infection.