title: AFM study of Escherichia coli RNA polymerase σ⁷⁰ subunit aggregation.
abstract: The self-assembly of Escherichia coli RNA polymerase σ⁷⁰ subunit was investigated using several experimental approaches. A novel rodlike shape was reported for σ⁷⁰ subunit aggregates. Atomic force microscopy reveals that these aggregates, or σ⁷⁰ polymers, have a straight rodlike shape 5.4 nm in diameter and up to 300 nm in length. Atomic force microscopy data, Congo red binding assay, and sodium dodecyl sulfate gel electrophoresis confirm the amyloid nature of observed aggregates. The process of formation of rodlike structures proceeds spontaneously under nearly physiological conditions. E. coli RNA polymerase σ⁷⁰ subunit may be an interesting object for investigation of amyloidosis as well as for biotechnological applications that exploit self-assembled bionanostructures. Polymerization of σ⁷⁰ subunit may be a competitive process with its three-dimensional crystallization and association with core RNA polymerase.
  
  
  BACKGROUND
  In this basic science study, the self-assembly of Escherichia coli RNA polymerase σ⁷⁰( subunit was investigated using atomic force microscopy and other complementary approaches.
authors.affiliation: Department of Physics of Polymers and Crystals, Faculty of Physics, Moscow State University, Russia. dubrovin@genebee.msu.ru
authors.forename: Evgeniy V
authors.initials: EV
authors.lastname: Dubrovin
authors.forename: Olga N
authors.initials: ON
authors.lastname: Koroleva
authors.forename: Yulia A
authors.initials: YA
authors.lastname: Khodak
authors.forename: Natalia V
authors.initials: NV
authors.lastname: Kuzmina
authors.forename: Igor V
authors.initials: IV
authors.lastname: Yaminsky
authors.forename: Valeriy L
authors.initials: VL
authors.lastname: Drutsa
mesh_terms: D000682:Amyloid / Q000737:chemistry / Q000648:ultrastructure; D003224:Congo Red / Q000737:chemistry; D012321:DNA-Directed RNA Polymerases / Q000737:chemistry* / Q000648:ultrastructure*; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000201:enzymology / Q000648:ultrastructure*; D046911:Macromolecular Substances / Q000737:chemistry / Q000648:ultrastructure*; D018625:Microscopy, Atomic Force / Q000379:methods; D010316:Particle Size; D012808:Sigma Factor / Q000737:chemistry* / Q000648:ultrastructure*
chemical_list: D000682:Amyloid; D046911:Macromolecular Substances; D012808:Sigma Factor; D003224:Congo Red; C081775:RNA polymerase sigma 70; D012321:DNA-Directed RNA Polymerases