Medicine and Health Sciences
The subcellular localization of the exoribonuclease RNase II is not known despite the advanced biochemical characterization of the enzyme. Here we report that RNase II is organized into cellular structures that appear to coil around the Escherichia coli cell periphery and that RNase II is associated with the cytoplasmic membrane by its aminoterminal amphipathic helix. The helix also acts as an autonomous transplantable membranebinding domain capable of directing normally cytoplasmic proteins to the membrane. Assembly of the organized cellular structures of RNase II required the RNase II amphipathic membrane-binding domain. Coimmunoprecipitation of the protein from cell extracts indicated that RNase II interacts with itself. The RNase II self-interaction and the ability of the protein to assemble into organized cellular structures required the membrane binding domain. The ability of RNase II to maintain cell viability in the absence of the exoribonuclease PNPase was markedly diminished when the RNase II cellular structures were lost due to changes in the amphipathicity of the N-terminal helix, suggesting that membrane association and assembly of RNase II into organized cellular structures play an important role in the normal function of the protein within the bacterial cell.
Lu, Feng and Taghbalout, Aziz, "Membrane Association via an N-terminal Amphipathic Helix is Required for the Cellular Organization and Function of RNase II" (2013). UCHC Articles - Research. 135.