Structural features and functional mechanism of TonB in some Gram-negative bacteria-A review

Abstract:

Abstract: TonB systems of gram-negative bacteria play an important role in transportation of nutriment from outside environments．TonB systems consist of plasma membrane proteins ExbB-ExbD and periplasmic protein TonB，which provide the energy to TonB-dependent receptors to transport substrates．These substrates include iron，hemin，vitamin B12，carbohydrate and some transition metal elements．The energy supporting function of TonB relies on its special structure which contains N-terminal domain for fixation，flexible periplasmic linker Pro-rich domain and C-terminal domain for contacting receptors．The precise mechanism of TonB system is not fully understood though its structural was studied a lot． To provide insights into direction for further research of TonB，we reviewed the TonB-dependent substrates uptake，structural features，functional mechanism and expression regulation of TonB.