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Site directed mutagenesis of subunit 8 of yeast mitochondrial ATP synthase
Author(s) -
Nero Debra,
Ekkel Sue M.,
Wang Lin-Fa,
Grasso David G.,
Nagley Phillip
Publication year - 1990
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(90)81235-g
Subject(s) - protein subunit , atp synthase , atp synthase gamma subunit , yeast , biochemistry , mitochondrion , mutagenesis , biology , saccharomyces cerevisiae , enzyme , mutation , gene , atpase , atp hydrolysis
The function of the positively charged C‐terminal region of mitochondrially encoded subunit 8 of yeast mitochondrial ATP synthase was investigated using derivatives truncated at each of the 3 positively charged residues (Arg 37 , Arg 42 and Lys 47 ). Each construct, allotopically expressed in the nucleus, was tested for its ability to import and assemble functionally into ATP synthase in yeast cells unable to synthesize mitochondrial subunit 8. The efficiency of import of each construct into isolated wild‐type yeast mitochondria was also determined. One construct truncated at the penultimate residue of subunit 8 (Lys 47 ) functions in vivo and shows efficient import in vitro. Thus subunit 8 can function with only two positively charged residues. The remainder of the subunit 8 variants failed to rescue in vivo. Since they all show greatly reduced or undetectable import in vitro, presumably because of the increased hydrophobic character of the subunit 8 moiety in the chimaeric precursors, the status of these variants as regards assembly and function is not clear.