Understanding how proteins interact with each other is a growing challenge in microbiology - it seems pretty important, but the analytical resolution on how such interactions happen and exactly how they modulate activity isn't quite up to the task yet. This work out of Steve Quake's lab uses microfluidic chambers to test binary protein-protein interactions and assign potential functions to partner proteins with unknown function. Abstract below, full paper [here].

Despite the enormous proliferation of bacterial genome data, surprisingly persistent collections of bacterial proteins have resisted functional annotation. In a typical genome, roughly 30% of genes have no assigned function. Many of these proteins are conserved across a large number of bacterial genomes. To assign a putative function to these conserved proteins of unknown function, we created a physical interaction map by measuring biophysical interaction of these proteins. Binary protein-–protein interactions in the model organism Streptococcus pneumoniae (TIGR4) are measured with a microfluidic high-throughput assay technology. In some cases, informatic analysis was used to restrict the space of potential binding partners. In other cases, we performed in vitro proteome-wide interaction screens. We were able to assign putative functions to 50 conserved proteins of unknown function that we studied with this approach.