Functional Dissection of a Viral DNA Packaging Machine's Walker B Motif.

ABSTRACT: Many viruses employ ATP-powered motors for genome packaging. We combined genetic, biochemical, and single-molecule techniques to confirm the predicted Walker-B ATP-binding motif in the phage λ motor and to investigate the roles of the conserved residues. Most changes of the conserved hydrophobic residues resulted in >10⁷-fold decrease in phage yield, but we identified nine mutants with partial activity. Several were cold-sensitive, suggesting that mobility of the residues is important. Single-molecule measurements showed that the partially active A175L exhibits a small reduction in motor velocity and increase in slipping, consistent with a slowed ATP binding transition, whereas G176S exhibits decreased slipping, consistent with an accelerated transition. All changes to the conse

SUBMITTER: delToro D 

PROVIDER: S-EPMC7416571 | biostudies-literature | 2019 Nov

REPOSITORIES: biostudies-literature