Bacterial spores are wonders of nature that can absorb a variety of insults, yet still germinate into viable cells when conditions become favorable. The spore coat enables much of this capability, but amazingly, very little is known about many coat proteins. We reveal and explore a new family of spore coat proteins, the bacterial spore kinases (BSKs). In collaboration with the Joint Center for Structural Genomics, we examine the family all the way from sequence and evolution to a detailed exploration of a representative structure, YtaA.
Our study reveals a dynamic family of proteins that appear to have undergone multiple independent duplications in various spore-forming gram-positive bacteria. Remarkably, though the family is related to known kinase enzymes, many members have lost key catalytic residues and are predicted to be pseudokinases. We also use evolutionary constraint analysis to predict the substrate binding region, and surmise that active BSKs will probably phosphorylate distinct substrates. These patterns suggest that BSKs have undergone a variety of changes that allow their hosts to adapt to specific challenges in their environment.
This sort of combined analysis may serve as a model to transform the huge new datasets of genome sequences and structural genomics targets into a unified understanding of previously unstudied protein families.
Genomics, Evolution, and Crystal Structure of a New Family of Bacterial Spore Kinases
Scheeff ED, Axelrod HL, Miller MD, Chiu HJ, Deacon AM, Wilson IA, and Manning G (2009) Proteins: Structure, Function, and Bioinformatics, 78(6):1470-82 (Medline, HTML, PDF, Feature in PSI-Nature SGK)