The chloroplast CF0I subunit can replace the b-subunit of the F0F1-ATPase in a mutant strain of Escherichia coli K12.
The amino acid sequence of the CF0I subunit from the chloroplast F0F1-ATPase has only a low similarity to the amino acid sequence of the b-subunit of the E. coli F0F1-ATPase. However, secondary and tertiary structure predictions plus the distribution of hydrophobic and hydrophilic amino acids have indicated that these two subunits serve a similar function. This proposition was investigated directly. A cDNA clone for the chloroplast atpF gene, encoding the CF0I subunit, was altered by site-directed mutagensis such that the translation start site corresponded to the N-terminus of the mature protein. An E. coli mutant strain carrying a chain-terminating mutation in the uncF gene, encoding the b-subunit, was transformed with the plasmid carrying the altered atpF gene. The resultant transformant was able to grow on succinate and gave a growth yield similar to that of a wild-type control. Assays on membrane preparations from the transformant also clearly indicated that the mature CF0I subunit from spinach chloroplasts was able to replace the E. coli b-subunit in the E. coli F0F1-ATPase.
Schmidt
G
G
Division of Biochemistry and Molecular Biology, John Curtin School of Medical Research, Australian National University, Canberra City.
Rodgers
A J
AJ
Howitt
S M
SM
Munn
A L
AL
Hudson
G S
GS
Holten
T A
TA
Whitfeld
P R
PR
Bottomley
W
W
Gibson
F
F
Cox
G B
GB
D000595:Amino Acid Sequence; D002736:Chloroplasts / Q000201:enzymology*; D004926:Escherichia coli / Q000201:enzymology* / Q000254:growth & development; D005816:Genetic Complementation Test; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D006180:Proton-Translocating ATPases / Q000378:metabolism*; D011994:Recombinant Proteins
D046911:Macromolecular Substances; D011994:Recombinant Proteins; D006180:Proton-Translocating ATPases