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Escherichia coli ’s aerobic growth is diminished by small C‐terminal deletions in the regulatory ε subunit of ATP synthase (615.1)
Author(s) -
Shah Naman,
Duncan Thomas
Publication year - 2014
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.28.1_supplement.615.1
Subject(s) - ctd , atp synthase , in vivo , protein subunit , enzyme , biochemistry , biology , atp synthase gamma subunit , escherichia coli , atpase , mutant , chemistry , gene , genetics , atp hydrolysis , oceanography , geology
F O F 1 ATP synthase is a rotary nanomotor involved in energy metabolism. It is also a target of antimicrobial drugs. In bacteria, the ε subunit can inhibit the enzyme with its C‐terminal domain (CTD), which partially enters the rotor cavity to block functional rotation. However, the in vivo role of ε inhibition is unclear since, with the entire εCTD absent, E. coli can grow to nearly normal levels on a non‐fermentable carbon source such as succinate. In the inhibited enzyme, the terminal segment of εCTD is deeply buried in the rotor cavity and interacts with one catalytic subunit. To test the importance of this final segment of εCTD, we genetically truncated the last 5 (εdel5) or last 10 (εdel10) amino acids of εCTD. Growth on succinate was reduced 蠅50% with εdel5 and the effect was similar with εdel10. Thus, perturbing interactions of εCTD with the enzyme is more detrimental to in vivo function than removing the entire εCTD. Initial assays with isolated mutant membranes show i) ATPase activity similar to wild‐type membranes and ii) no dramatic effects on the coupling between the catalytic (F 1 ) and H + ‐transporting (F O ) complexes. Other in vitro tests are in progress to determine how these truncations diminish the in vivo capacity for respiratory synthesis of ATP. This finding indicates compounds that perturb ε’s regulatory interactions could provide a means to prohibit aerobic growth. Grant Funding Source : Supported by R01GM083088