PMID:11412108

Citation	Tucker, WC, Du, Z, Hein, R, Gromet-Elhanan, Z and Richter, ML (2001) Role of the ATP synthase alpha-subunit in conferring sensitivity to tentoxin. Biochemistry 40:7542-8
Abstract	Tentoxin, produced by phytopathogenic fungi, selectively affects the function of the ATP synthase enzymes of certain sensitive plant species. Binding of tentoxin to a high affinity (K(i) approximately 10 nM) site on the chloroplast F(1) (CF(1)) strongly inhibits catalytic function, whereas binding to a second, lower affinity site (K(d) > 10 microM) leads to restoration and even stimulation of catalytic activity. Sensitivity to tentoxin has been shown to be due, in part, to the nature of the amino acid residue at position 83 on the catalytic beta subunit of CF(1). An aspartate in this position is required, but is not sufficient, for tentoxin inhibition. By comparison with the solved structure of mitochondrial F(1) [Abrahams, J. P., Leslie, A. G. W., Lutter, R., and Walker, J. E. (1994) Nature 370, 621-628], Asp83 is probably located at an interface between alpha and beta subunits on CF(1) where residues on the alpha subunit could also participate in tentoxin binding. A hybrid core F(1) enzyme assembled with beta and gamma subunits of the tentoxin-sensitive spinach CF(1), and an alpha subunit of the tentoxin-insensitive photosynthetic bacterium Rhodospirillum rubrum F(1) (RrF(1)), was stimulated but not inhibited by tentoxin [Tucker, W. C., Du, Z., Gromet-Elhanan, Z. and Richter, M. L. (2001) Eur. J. Biochem. 268, 2179-2186]. In this study, chimeric alpha subunits were prepared by introducing short segments of the spinach CF(1) alpha subunit from a poorly conserved region which is immediately adjacent to beta-Asp83 in the crystal structure, into equivalent positions in the RrF(1) alpha subunit using oligonucleotide-directed mutagenesis. Hybrid enzymes containing these chimeric alpha subunits had both the high affinity inhibitory tentoxin binding site and the lower affinity stimulatory site. Changing beta-Asp83 to leucine resulted in loss of both inhibition and stimulation by tentoxin in the chimeras. The results indicate that tentoxin inhibition requires additional alpha residues that are not present on the RrF(1) alpha subunit. A structural model of a putative inhibitory tentoxin binding pocket is presented.
Links	PubMed
Keywords	Amino Acid Sequence; Binding Sites/genetics; Ca(2+) Mg(2+)-ATPase/genetics; Ca(2+) Mg(2+)-ATPase/metabolism; Calcium-Transporting ATPases/genetics; Calcium-Transporting ATPases/metabolism; Dose-Response Relationship, Drug; Enzyme Inhibitors/metabolism; Enzyme Inhibitors/toxicity; Molecular Sequence Data; Mycotoxins/metabolism; Mycotoxins/toxicity; Peptide Fragments/antagonists & inhibitors; Peptide Fragments/genetics; Peptide Fragments/metabolism; Peptides, Cyclic/metabolism; Peptides, Cyclic/toxicity; Proton-Translocating ATPases/antagonists & inhibitors; Proton-Translocating ATPases/genetics; Proton-Translocating ATPases/metabolism; Recombinant Fusion Proteins/antagonists & inhibitors; Recombinant Fusion Proteins/chemical synthesis; Recombinant Fusion Proteins/metabolism; Rhodospirillum rubrum/enzymology; Spinacia oleracea/enzymology
edit table

Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
RHORU:ATPA		GO:0006754: ATP biosynthetic process	ECO:0000314:		P		See figure 3 from paper.	complete CACAO 3329
RHORU:ATPA	involved_in	GO:0006754: ATP biosynthetic process	ECO:0000314: direct assay evidence used in manual assertion		P		Seeded From UniProt	complete

References

See Help:References for how to manage references in GONUTS.