Аннотация:In this work, atomic force microscopy (AFM) was used for investigation of structure and conditions of formation of rodlike amyloid aggregates (fibrils) of Escherichia coli RNA polymerase sigma(70) subunit. These aggregates have straight cylindrical shape based on a helical structure with diameter 5.4 nm and length from several tens nanometers up to several microns. We have demonstrated that sigma(70) subunit forms amyloid aggregates under a wide range of cationic concentrations including physiological ones. Based om AFM data of fibril formation of three different mutant proteins, devoid the whole 1.1 region (N-terminus) or its part, we propose a model of sigma(70) subunit aggregation, which is based on the domain swapping mechanism.