Reconstitution of a nanomachine driving the assembly of proteins into bacterial outer membranes

In biological membranes, various protein secretion devices function as nanomachines, and measuring the internal movements of their component parts is a major technological challenge. The translocation and assembly module (TAM) is a nanomachine required for virulence of bacterial pathogens. We have reconstituted a membrane containing the TAM onto a gold surface for characterization by quartz crystal microbalance with dissipation (QCM-D) and magnetic contrast neutron reflectrometry (MCNR). The MCNR studies provided structural resolution down to 1 Å, enabling accurate measurement of protein domains projecting from the membrane layer. Here we show that dynamic movements within the TamA component of the TAM are initiated in the presence of a substrate protein, Ag43, and that these movements recapitulate an initial stage in membrane protein assembly. The reconstituted system provides a powerful new means to study molecular movements in biological membranes, and the technology is widely applicable to studying the dynamics of diverse cellular nanomachines. © Macmillan Publishers Limited

Keywords

Membranes, Pathogens, Proteins, Molecules, Neutron reflectors, Pathogens

Citation

Shen, H.-H., Leyton, D. L., Shiota, T., Belousoff, M. J., Noinaj, N., Lu, J., Holt, S. A., Tan, K., Selkrig, J., Webb, C. T., Buchanan, S. K., Martin, L. L., & Lithgow, T. (2014). Reconstitution of a nanomachine driving the assembly of proteins into bacterial outer membranes. Nature Communications, 5, 1-10, 5078. doi:10.1038/ncomms6078