HS-291 is a HtpG inhibitor of Borrelia burgdorferi (Bb). HS-291 contains BX-2819 (high affinity for Bb HtpG ), PEG linker, and Verteporfin (a photoactive toxin).HS-291 produces reactive oxygen species under light activation to oxidize HtpG and a discrete protein subset near chaperone proteins and can quickly and irreversibly inactivate Bb.