Intersubunit coordination in a homomeric ring ATPase

Jeffrey R. Moffitt, Yann R. Chemla, K. Aathavan, Shelley Grimes, Paul J. Jardine, Dwight L. Anderson, Carlos Bustamante

Research output: Contribution to journalArticlepeer-review

203 Scopus citations


Homomeric ring ATPases perform many vital and varied tasks in the cell, ranging from chromosome segregation to protein degradation. Here we report the direct observation of the intersubunit coordination and step size of such a ring ATPase, the double-stranded-DNA packaging motor in the bacteriophage φ29. Using high-resolution optical tweezers, we find that packaging occurs in increments of 10 base pairs (bp). Statistical analysis of the preceding dwell times reveals that multiple ATPs bind during each dwell, and application of high force reveals that these 10-bp increments are composed of four 2.5-bp steps. These results indicate that the hydrolysis cycles of the individual subunits are highly coordinated by means of a mechanism novel for ring ATPases. Furthermore, a step size that is a non-integer number of base pairs demands new models for motor-DNA interactions.

Original languageEnglish (US)
Pages (from-to)446-450
Number of pages5
Issue number7228
StatePublished - Jan 22 2009

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