The Structure And Function Of E.coli Era And Its Interactional Protein

Era(E.coli Ras-like protein Era) is a GTPase and essential for Escherichia coli viability. Homologues of Era have been identified in prokaryotes and eukaryotes. There are two domains in Era: The N-terminal GTP-binding domain and C- terminal RNA binding KH domain. Era plays an important role in cell cycle progression at a specific point in the cycle, after chromosome partitioning but before cytokinesis. In our previous study, YggG, SpeB were found in 2. 8kb DNA fragment that could bound Era probe by using E. coli genome phage expression library to screen Era binding protein. Possible interactions between Era and YggG, SpeB were analyzed. The results suggested that Era dimmer and SpeB dimmer might exist in Escherichia coli. Over-expression of YggG retarded the cell cycle, on the point after DNA partition, resulting in accumulationof diploid as bacteria stop division and sequentially went to death. This appearance is similar to that of the Era mutants, including the partially defective in Era GTPase activity or the reduced in the synthesis of wild-type Era which bacteria become arrested in the cycle at the predivisional two-cell stage. DY330(AyggG) and DY331(AyggG) showed green color after yggG was knocked out. As analysis by bioinformatics, YggG belongs to Peptidase_M48 family which contains HEXXH motif that forms a metal binding site. Era contains 97 possible cutting sites that can be recognized by thermolysin which belong to the same family with YggG. Our results suggest that possible interaction between YggG and Era leads to cell cycle arrested. YggG may be a negative regulator of Era.