The signature motif of the Saccharomyces cerevisiae Pif1 DNA helicase is essential in vivo for mitochondrial and nuclear functions and in vitro for ATPase activity.

TitleThe signature motif of the Saccharomyces cerevisiae Pif1 DNA helicase is essential in vivo for mitochondrial and nuclear functions and in vitro for ATPase activity.
Publication TypeJournal Article
Year of Publication2018
AuthorsGeronimo, CL, Singh, SP, Galletto, R, Zakian, VA
JournalNucleic Acids Res
Volume46
Issue16
Pagination8357-8370
Date Published2018 Sep 19
ISSN1362-4962
Abstract

Pif1 family DNA helicases are conserved from bacteria to humans and have critical and diverse functions in vivo that promote genome integrity. Pif1 family helicases share a 23 amino acid region, called the Pif1 signature motif (SM) that is unique to this family. To determine the importance of the SM, we did mutational and functional analysis of the SM from the Saccharomyces cerevisiae Pif1 (ScPif1). The mutations deleted portions of the SM, made one or multiple single amino acid changes in the SM, replaced the SM with its counterpart from a bacterial Pif1 family helicase and substituted an α-helical domain from another helicase for the part of the SM that forms an α helix. Mutants were tested for maintenance of mitochondrial DNA, inhibition of telomerase at telomeres and double strand breaks, and promotion of Okazaki fragment maturation. Although certain single amino acid changes in the SM can be tolerated, the presence and sequence of the ScPif1 SM were essential for all tested in vivo functions. Consistent with the in vivo analyses, in vitro studies showed that the presence and sequence of the ScPif1 SM were critical for ATPase activity but not substrate binding.

DOI10.1093/nar/gky655
Alternate JournalNucleic Acids Res.
PubMed ID30239884
PubMed Central IDPMC6144861