Abstract
Protein interaction networks shed light on the global organization of proteomes but can also place individual proteins into a functional context. If we know the function of bacterial proteins we will be able to understand how these species have adapted to diverse environments including many extreme habitats. Here we present the protein interaction network for the syphilis spirochete Treponema pallidum which encodes 1,039 proteins, 726 (or 70%) of which interact via 3,649 interactions as revealed by systematic yeast two-hybrid screens. A high-confidence subset of 991 interactions links 576 proteins. To derive further biological insights from our data, we constructed an integrated network of proteins involved in DNA metabolism. Combining our data with additional evidences, we provide improved annotations for at least 18 proteins (including TP0004, TP0050, and TP0183 which are suggested to be involved in DNA metabolism). We estimate that this “minimal” bacterium contains on the order of 3,000 protein interactions. Profiles of functional interconnections indicate that bacterial proteins interact more promiscuously than eukaryotic proteins, reflecting the non-compartmentalized structure of the bacterial cell. Using our high-confidence interactions, we also predict 417,329 homologous interactions (“interologs”) for 372 completely sequenced genomes and provide evidence that at least one third of them can be experimentally confirmed.
Highlights
Most bacterial genomes encode hundreds or even thousands of proteins of unknown function [1]
We suggest that interactions found in species such as T. pallidum be verified in more mainstream model organisms such as E. coli
Generation of a comprehensive binary proteininteraction map and quality control Yeast-two-hybrid screening for the T. pallidum proteome was conducted in a systematic array-based format as described previously [14,17]
Summary
Most bacterial genomes encode hundreds or even thousands of proteins of unknown function [1]. If we want to understand the biology of these organisms, we need to understand the role of their proteins. One way to unravel the molecular function of a protein is to identify interacting proteins [2]. The protein networks of only three organisms have been comprehensively investigated. Systematic purification of protein complexes and their identification by mass spectrometry has recently been completed in both budding yeast and Escherichia coli [3,4,5]. It became clear that these studies recovered only a fraction of all complexes and interactions [6] and it is still unclear how many interactions take place in a cell since no organism has been sampled exhaustively. For the majority of interactions it remains unclear what their biological significance is
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
