| Abstrakt: |
Simple Summary: DNA gyrase is an essential hub in bacteria that is targeted by small proteins found throughout the prokaryotic world. We explore the state of knowledge on potential roles for these gyrase inhibitors, including competition between mobile genetic elements and other cellular conflicts. Interestingly, a growing number of these inhibitors appear to protect gyrase by reversibly inhibiting its function. These intriguing mechanisms provide a glimpse into a complicated interplay of gyrase targeting and regulation. We anticipate that the underlying molecular mechanisms will be useful for antibacterial development in the face of increasing resistance to gyrase-targeting treatments. DNA gyrase is essential for the successful replication of circular chromosomes, such as those found in most bacterial species, by relieving topological stressors associated with unwinding the double-stranded genetic material. This critical central role makes gyrase a valued target for antibacterial approaches, as exemplified by the highly successful fluoroquinolone class of antibiotics. It is reasonable that the activity of gyrase could be intrinsically regulated within cells, thereby helping to coordinate DNA replication with doubling times. Numerous proteins have been identified to exert inhibitory effects on DNA gyrase, although at lower doses, it can appear readily reversible and therefore may have regulatory value. Some of these, such as the small protein toxins found in plasmid-borne addiction modules, can promote cell death by inducing damage to DNA, resulting in an analogous outcome as quinolone antibiotics. Others, however, appear to transiently impact gyrase in a readily reversible and non-damaging mechanism, such as the plasmid-derived Qnr family of DNA-mimetic proteins. The current review examines the origins and known activities of protein inhibitors of gyrase and highlights opportunities to further exert control over bacterial growth by targeting this validated antibacterial target with novel molecular mechanisms. Furthermore, we are gaining new insights into fundamental regulatory strategies of gyrase that may prove important for understanding diverse growth strategies among different bacteria. [ABSTRACT FROM AUTHOR] |
