Work

Nucleotide-dependent DNA gripping and an end-clamp mechanism regulate the bacteriophage T4 viral packaging motor

Year: 2018

Type: article

Abstract: ATP-powered viral packaging motors are among the most powerful biomotors known. Motor subunits arranged in a ring repeatedly grip and translocate the DNA to package viral genomes into capsids. Here, we use single DNA manipulation and rapid solution exchange to quantify how nucleotide binding regulates interactions between the bacteriophage T4 motor and DNA substrate. With no nucleotides, there is virtually no gripping and rapid slipping occurs with only minimal friction resisting. In contrast, binding of an ATP analog engages nearly continuous gripping. Occasional slips occur due to dissociation of the analog from a gripping motor subunit, or force-induced rupture of grip, but multiple other analog-bound subunits exert high friction that limits slipping. ADP induces comparably infrequent gripping and variable friction. Independent of nucleotides, slipping arrests when the end of the DNA is about to exit the capsid. This end-clamp mechanism increases the efficiency of packaging by making it essentially irreversible.

Source: Nature Communications

DOI: 10.1038/s41467-018-07834-2

Authors: Mariam Ordyan, Istiaq Alam, Marthandan Mahalingam, Venigalla B. Rao, Douglas E. Smith

Institutions: University of California San Diego, Catholic University of America

Language: English

Topic: Force Microscopy Techniques and Applications

Subfield: Atomic and Molecular Physics, and Optics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $6,990

Funders: National Science Foundation, National Institutes of Health, National Institute of General Medical Sciences, National Institute of Allergy and Infectious Diseases