As current events dramatically indicate, reliable accurate and portable Bacillus anthracis spore detection systems are critical for national defense and civilian health. In an effort to meet this need, several candidate technologies are under examination by a number of federal agencies. Detectors using the outermost proteins of the spore coat as signature molecules for identification would represent a particularly compelling technology. This approach is not currently feasible, as the identities of the B. anthracis surface proteins are unknown. However, based on the completed B. anthracis genome sequence and extensive analysis of the related organism B. subtilis, we can now identify many spore-surface protein candidates. In addition, a variety of approaches to identify these proteins de novo are available. Therefore, we propose using a combination of biochemical and genetic methods to test candidate proteins for a surface location as well as to identify these proteins directly. Our approaches take advantage of proteomic analysis of the B. anthracis and B. subtilis coats ongoing in our laboratory, as well as the available genome sequences of the two organisms. Ultimately, this work will enable development of a new class of small, robust versatile B. anthracis spore detectors. ? ?