Reconstructing the coordinated self-assembly of a bacterial nanomachine

Descripción del proyecto

Comprender el autoensamblaje de múltiples proteínas en nanomáquinas funcionales

Las bacterias se desplazan con sus flagelos, apéndices en forma de hélice que permiten un movimiento dirigido hacia los nutrientes, otros atrayentes y los sitios preferidos para desarrollar una infección. Un motor situado en la membrana celular gira el filamento del flagelo, de unos 20 nm de diámetro. Todo el flagelo es una complicada nanomáquina en la que múltiples proteínas forman los anillos que anclan el flagelo en la membrana, actúan como motor y forman el propio filamento. Mientras que otros estudios se han centrado en la genética y la caracterización de los subcomponentes, el proyecto BacNanoMachine, financiado con fondos europeos, planea mejorar nuestra comprensión del autoensamblaje coordinado de todos los componentes básicos de las bacterias en el tiempo y el espacio. Servirá para entender mejor estos procesos y también podrá tener repercusiones en el diseño racional de nuevos antibióticos y para diversas aplicaciones de las máquinas moleculares sintéticas.

Objetivo

Life has evolved diverse protein machines and bacteria provide many fascinating examples. Despite being unicellular organisms of relatively small size, bacteria produce sophisticated nanomachines with a high degree of self-organization. The motility organelle of bacteria, the flagellum, is a prime example of complex bacterial nanomachines. Flagella are by far the most prominent extracellular structures known in bacteria and made through self-assembly of several dozen different kinds of proteins and thus represents an ideal model system to study sub-cellular compartmentalization and self-organization. The flagellum can function as a macromolecular motility machine only if its many building blocks assemble in a coordinated manner. However, previous studies have focused on phenotypic and genetic analyses, or the characterization of isolated sub-components. Crucially, how bacteria orchestrate the many different cellular processes in time and space in order to construct a functional motility organelle remains enigmatic. The present proposal constitutes a comprehensive research program with the aim to obtain a holistic understanding of the underlying principles that allow bacteria to control and coordinate the simultaneous self-assembly processes of several multi-component nanomachines within a single cell. Towards this goal, we will combine for the first time the visualization of the dynamic self-assembly of individual flagella with quantitative single-cell gene expression analyses, re-engineering of the genetic network and biophysical modeling in order to develop a biophysical model of flagella self-assembly. This novel, integrative approach will allow us to move beyond the classical, descriptive characterization of protein complexes towards an engineering-type understanding of the extraordinarily robust and coordinated assembly of a multi-component molecular machine.