Identification of a 180kD protein in Escherichia coli related to a yeast heavy‐chain myosin

Abstract

A high molecular-weight protein from Escherichia coli sharing structural homology at the protein level with a yeast heavy-chain myosin encoded by the MYO1 gene is described. This 180 kD protein (180-HMP) can be enriched in cell fractions following the procedure normally utilized for the purification of non-muscle myosins. In Western blots this protein cross-reacts with a monoclonal antibody against yeast heavy-chain myosin. Moreover, antibodies raised against the 180 kD protein cross-react with the yeast myosin and with a myosin heavy chain from chicken. Recognition by anti-180-HMP antibodies of an overexpressed fragment of yeast myosin encoded by MYO1 allows the localization of one of the shared epitopes to a specific region around the ATP binding site of the yeast myosin heavy chain. The existence of a high molecular-weight protein with structural similarity to myosin in E. coli raises the possibility that such a protein might generate the force required for movement in processes such as nucleoid segregation and cell division.

Electric fields induce curved growth of Enterobacter cloacae, Escherichia coli, and Bacillus subtilis cells: implications for mechanisms of galvanotropism and bacterial growth

“…Cells were monitored during field exposure to determine whether this variation reflected the orientation of the cells at the beginning of field exposure (i.e., are ends of cells already parallel to the cathode/anode axis less prone to field-induced bending than perpendicular ones?). Quantitation of the galvanotropic response was complicated by cell division, so for most time lapse experiments, E. cloacae was treated with cephalexin, which induces filamentation (38 3. Individual E. cloacae cells growing in the presence and absence of an electric field.…”

“…Despite recent evidence that homologs of eukaryotic mechanopro,teins exist in bacteria (3,31), it is generally accepted that bacteria are naturally devoid of actin (22). We have therefore exploited the serendipitous discovery of a galvanotropic bacterium to explore the mechanisms that elicit fieldinduced directional growth.…”

Production of sound waves by bacterial cells and the response of bacterial cells to sound.

“…Sounds might be produced by repeated expansion and contraction. This might be accomplished by using intracellular structures, such as membranes, cytoskeleton-like structures (e.g., Casarégola et al, 1990;Okada et al, 1994) or chromosomes, through mechanisms that involve the conversion of ATP or membrane potentials to movement. Activation of an ion channel might be the mechanism for the perception of sound.…”

Bacillus carboniphilus cells respond to growth-promoting physical signals from cells of homologous and heterologous bacteria.

“…In bacteria, in which cytoskeletons have long been undetected, some candidate proteins are appearing recently (1,8). Extracellular organelles such as fragella and pili may be ruled out as candidates for the sonic generator of the cell, since organisms that do not have them such as MM luteus, S cerevisiae and plant cells can also emit (6) and high temperatures.…”