Figure 2

Functional ORFeomics. (A) Recombinant protein expression in E. coli. Western blot of 10 GST-tagged E. coli recombinant proteins. After induction of protein expression with IPTG, the cells were lysed and the crude lysates were analyzed by Western blot and antibody detection with anti-GST antibodies. The expected band sizes are marked by arrow heads, the lower molecular weight bands of DnaE are the results of protein degradation (B, C) E. coli, S. aureus and S. pneumoniae YgjD, YjeE and YeaZ proteins were tested by the yeast two-hybrid method for interactions. "+" indicate a positive protein interaction and "-" indicate no protein interaction; the pGADT7g-vector is a negative control (for autoactivation); uncertain interactions due to autoactivation are indicated by "A". (C) Intraspecies and interspecies protein interactions of YgjD and YeaZ of E. coli, S. aureus, S. pneumoniae, H. pylori, and R. prowazekii (as in B). (D) Interpretation of Figures (B) and (C). Crystal structures are available for YeaZ (PDB: 1OKJ), YjeE (1HTW-A), and YgjD (2IVO), but only YeaZ has been crystallized from E. coli. Comparative analyses show conserved residues and thus potential interaction sites (red: most, blue: least conserved). The strongest interactions (thick lines) also tend to be the most conserved ones.