Research Progress on The Structure and Mechanism ofBacterial Secretion Systems br

Bacterial secretion systems are sophisticated nanomachines that are used by bacteria for selectivetransport of macromolecules across membrane.These membrane protein complexes play critical roles in bacterialpathogenicity,antibiotic resistance and ecological adaptation.Hitherto,a total of nine secretion systems have beenidentified and named as type I to type IX secretion systems(T1SS-T9SS)according to the chronological order ofdiscovery.Recent advances in X-ray crystallography,nuclear magnetic resonance and cryo-electron microscopyincreased the understanding of the architecture and structure of these macromolecular machineries.That providedunprecedented views to explain the mechanisms of how secretion systems release the effectors to the extracellularenvironment or host cells.Herein,this review summarizes the best knowledge of the progress of bacterialsecretion systems(T1SS-T9SS),with a focus on their structure and function.We also highlight major advances innovel antimicrobials targeting these large protein machineries.Finally,we provide new perspectives for the futurestudies about structure identification and drug screening of secretion systems