AUTHOR=Panthee Suresh , Paudel Atmika , Hamamoto Hiroshi , Uhlemann Anne-Catrin , Sekimizu Kazuhisa 

TITLE=The Role of Amino Acid Substitution in HepT Toward Menaquinone Isoprenoid Chain Length Definition and Lysocin E Sensitivity in Staphylococcus aureus

JOURNAL=Frontiers in Microbiology

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2020.02076

DOI=10.3389/fmicb.2020.02076

ISSN=1664-302X

ABSTRACT=<sec><title>Objectives</title><p><italic>Staphylococcus aureus</italic> Smith strain is a historical strain widely used for research purposes in animal infection models for testing the therapeutic activity of antimicrobial agents. We found that it displayed higher sensitivity toward lysocin E, a menaquinone (MK) targeting antibiotic, compared to other <italic>S. aureus</italic> strains. Therefore, we further explored the mechanism of this hypersensitivity.</p></sec><sec><title>Methods</title><p>MK production was analyzed by high-performance liquid chromatography and mass spectrometric analysis. <italic>S. aureus</italic> Smith genome sequence was completed using a hybrid assembly approach, and the MK biosynthetic genes were compared with other <italic>S. aureus</italic> strains. The <italic>hepT</italic> gene was cloned and introduced into <italic>S. aureus</italic> RN4220 strain using phage mediated recombination, and lysocin E sensitivity was analyzed by the measurement of colony-forming units.</p></sec><sec><title>Results</title><p>We found that Smith strain produced MKs with the length of the side chain ranging between 8 and 10, as opposed to other <italic>S. aureus</italic> strains that produce MKs 7–9. We revealed that Smith strain possessed the classical pathway for MK biosynthesis like the other <italic>S. aureu</italic>s. HepT, a polyprenyl diphosphate synthase involved in chain elongation of isoprenoid, in Smith strain harbored a Q25P substitution. Introduction of <italic>hepT</italic> from Smith to RN4220 led to the production of MK-10 and an increased sensitivity toward lysocin E.</p></sec><sec><title>Conclusion</title><p>We found that HepT was responsible for the definition of isoprenoid chain length of MKs and antibiotic sensitivity.</p></sec>