The effect of nucleotides and mitochondrial chaperonin 10 on the structure and chaperone activity of mitochondrial chaperonin 60.
Mitochondrial chaperonins are necessary for the folding of newly imported and stress-denatured mitochondrial proteins. The goal of this study was to investigate the structure and function of the mammalian mitochondrial chaperonin system. We present evidence that the 60 kDa chaperonin (mt-cpn60) exists in solution in dynamic equilibrium between monomers, heptameric single rings and double-ringed tetradecamers. In the presence of ATP and the 10 kDa cochaperonin (mt-cpn10), the formation of a double ring is favored. ADP at very high concentrations does not inhibit malate dehydrogenase refolding or ATP hydrolysis by mt-cpn60 in the presence of mt-cpn10. We propose that the cis (mt-cpn60)14.nucleotide.(mt-cpn10)7 complex is not a stable species and does not bind ADP effectively at its trans binding site.
Levy-Rimler
G
G
Department of Biochemistry, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Israel.
Viitanen
P
P
Weiss
C
C
Sharkia
R
R
Greenberg
A
A
Niv
A
A
Lustig
A
A
Delarea
Y
Y
Azem
A
A
D000244:Adenosine Diphosphate / Q000494:pharmacology*; D000251:Adenosine Triphosphatases / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D018835:Chaperonin 10 / Q000494:pharmacology*; D018834:Chaperonin 60 / Q000737:chemistry* / Q000378:metabolism*; D008291:Malate Dehydrogenase / Q000737:chemistry / Q000378:metabolism; D008854:Microscopy, Electron; D008929:Mitochondria, Heart / Q000378:metabolism*; D011489:Protein Denaturation; D013329:Structure-Activity Relationship; D013552:Swine; D014508:Urea / Q000737:chemistry
D018835:Chaperonin 10; D018834:Chaperonin 60; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D014508:Urea; D008291:Malate Dehydrogenase; D000251:Adenosine Triphosphatases