Quantitative description of a contractile macromolecular machine

Alec Fraser, Nikolai Prokhorov, Fang Jiao, B. Montgomery Pettitt, Simon Scheuring, Petr G. Leiman

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


Contractile injection systems (CISs) [type VI secretion system (T6SS), phage tails, and tailocins] use a contractile sheath-rigid tube machinery to breach cell walls and lipid membranes. The structures of the pre- and postcontraction states of several CISs are known, but the mechanism of contraction remains poorly understood. Combining structural information of the end states of the 12-megadalton R-type pyocin sheath-tube complex with thermodynamic and force spectroscopy analyses and an original modeling procedure, we describe the mechanism of pyocin contraction. We show that this nanomachine has an activation energy of 160 kilocalories/mole (kcal/mol), and it releases 2160 kcal/mol of heat and develops a force greater than 500 piconewtons. Our combined approach provides a quantitative and experimental description of the membrane penetration process by a CIS.

Original languageEnglish (US)
Article numbereabf9601
JournalScience Advances
Issue number24
StatePublished - Jun 2021

ASJC Scopus subject areas

  • General


Dive into the research topics of 'Quantitative description of a contractile macromolecular machine'. Together they form a unique fingerprint.

Cite this