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Intergenic suppression in a β subunit mutant with defective assembly in Escherichia coli F 1 ATPase
Author(s) -
Miki Junji,
Tsugumi Sadamu,
Ikeda Hiromi,
Kanazawa Hiroshi
Publication year - 1994
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(94)00390-4
Subject(s) - protein subunit , mutant , escherichia coli , microbiology and biotechnology , specificity factor , biology , plasmid , gene , atpase , mutation , scn3a , g alpha subunit , genetics , biochemistry , enzyme , rna polymerase
Substitution of Leu‐40 by Pro in the β subunit (βL40P) of Escherichia coli F 1 ‐ATPase caused a decrease in the amount of the α and β subunits on the membranes. A revertant strain, Re50, carrying no suppression mutations in the unc D gene encoding the β subunit, was isolated from the βL40P mutant. The uncA gene from this revertant was amplified by PCR, and cloned into an expression plasmid. The expression plasmid carrying the uncA gene from the revertant was used for genetic suppression assays. The suppression mutation in Re50 was in the α subunit, and it recovered the assembly of the α and β subunits into the F 1 F 0 complex and the ATPase activity to 50% that of the wild type. In Re50, Leu‐111 was substituted by Gln in the α subunit. These results suggest that the regions including Leu‐40 in the β subunit and Leu‐111 in the α subunit are located close together and interact with each other, either directly or indirectly.