Novel actin-like filament structure from Clostridium tetani

David Popp, Akihiro Narita, Lin Jie Lee, Umesh Ghoshdastider, Bo Xue, Ramanujam Srinivasan, Mohan K. Balasubramanian, Toshitsugu Tanaka, Robert C. Robinson

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Abstract

Eukaryotic F-actin is constructed from two protofilaments that gently wind around each other to form a helical polymer. Several bacterial actin-like proteins (Alps) are also known to form F-actin-like helical arrangements from two protofilaments, yet with varied helical geometries. Here, we report a unique filament architecture of Alp12 from Clostridium tetani that is constructed from four protofilaments. Through fitting of an Alp12 monomer homology model into the electron microscopy data, the filament was determined to be constructed from two antiparallel strands, each composed of two parallel protofilaments. These four protofilaments form an open helical cylinder separated by a wide cleft. The molecular interactions within single protofilaments are similar to F-actin, yet interactions between protofilaments differ from those in F-actin. The filament structure and assembly and disassembly kinetics suggest Alp12 to be a dynamically unstable force-generating motor involved in segregating the pE88 plasmid, which encodes the lethal tetanus toxin, and thus a potential target for drug design. Alp12 can be repeatedly cycled between states of polymerization and dissociation, making it a novel candidate for incorporation into fuel-propelled nanobiopolymer machines.

Original languageEnglish
Pages (from-to)21121-21129
Number of pages9
JournalJournal of Biological Chemistry
Volume287
Issue number25
DOIs
Publication statusPublished - Jun 15 2012
Externally publishedYes

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ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Cite this

Popp, D., Narita, A., Lee, L. J., Ghoshdastider, U., Xue, B., Srinivasan, R., Balasubramanian, M. K., Tanaka, T., & Robinson, R. C. (2012). Novel actin-like filament structure from Clostridium tetani. Journal of Biological Chemistry, 287(25), 21121-21129. https://doi.org/10.1074/jbc.M112.341016