AUTHOR=Chmielewska-Jeznach Magdalena , Steczkiewicz Kamil , Kobyłecki Kamil , Bardowski Jacek K. , Szczepankowska Agnieszka K. 

TITLE=An Adenosine Triphosphate- Dependent 5′-3′ DNA Helicase From sk1-Like Lactococcus lactis F13 Phage

JOURNAL=Frontiers in Microbiology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.840219

DOI=10.3389/fmicb.2022.840219

ISSN=1664-302X

ABSTRACT=<p>Here, we describe functional characterization of an early gene (<italic>gp46</italic>) product of a virulent <italic>Lactococcus lactis</italic> sk1<italic>-</italic>like phage, vB_Llc_bIBBF13 (abbr. F13). The GP46<sub><italic>F</italic>13</sub> protein carries a catalytically active RecA-like domain belonging to the P-loop NTPase superfamily. It also retains features characteristic for ATPases forming oligomers. In order to elucidate its detailed molecular function, we cloned and overexpressed the <italic>gp46</italic> gene in <italic>Escherichia coli</italic>. Purified GP46<sub><italic>F</italic>13</sub> protein binds to DNA and exhibits DNA unwinding activity on branched substrates in the presence of adenosine triphosphate (ATP). Size exclusion chromatography with multi-angle light scattering (SEC-MALS) experiments demonstrate that GP46<sub><italic>F</italic>13</sub> forms oligomers, and further pull-down assays show that GP46<sub><italic>F</italic>13</sub> interacts with host proteins involved in replication (i.e., DnaK, DnaJ, topoisomerase I, and single-strand binding protein). Taking together the localization of the gene and the obtained results, GP46<sub><italic>F</italic>13</sub> is the first protein encoded in the early-expressed gene region with helicase activity that has been identified among lytic <italic>L. lactis</italic> phages up to date.</p>