Probing conformations of the β subunit of F0F1-ATP synthase in catalysis

2006 ◽  
Vol 342 (3) ◽  
pp. 800-807 ◽  
Author(s):  
Tomoko Masaike ◽  
Toshiharu Suzuki ◽  
Satoshi P. Tsunoda ◽  
Hiroki Konno ◽  
Masasuke Yoshida
1998 ◽  
Vol 330 (2) ◽  
pp. 707-712 ◽  
Author(s):  
J. Christian KETCHUM ◽  
Marwan K. AL-SHAWI ◽  
K. Robert NAKAMOTO

We previously demonstrated that the Escherichia coli F0F1-ATP synthase mutation, γM23K, caused increased energy of interaction between γ- and β-subunits which was correlated to inefficient coupling between catalysis and transport [Al-Shawi, Ketchum and Nakamoto (1997) J. Biol. Chem. 272, 2300-2306]. Based on these results and the X-ray crystallographic structure of bovine F1-ATPase [Abrahams, Leslie, Lutter and Walker (1994) Nature (London) 370, 621-628] γM23K is believed to form an ionized hydrogen bond with βGlu-381 in the conserved β380DELSEED386 segment. In this report, we further test the role of γ-β-subunit interactions by introducing a series of substitutions for βGlu-381 and γArg-242, the residue which forms a hydrogen bond with βGlu-381 in the wild-type enzyme. βE381A, D, and Q were able to restore efficient coupling when co-expressed with γM23K. All three mutations reversed the increased transition state thermodynamic parameters for steady state ATP hydrolysis caused by γM23K. βE381K by itself caused inefficient coupling, but opposite from the effect of γM23K, the transition state thermodynamic parameters were lower than wild-type. These results suggest that the βE381K mutation perturbs the γ-β-subunit interaction and the local conformation of the β380DELSEED386 segment in a specific way that disrupts the communication of coupling information between transport and catalysis. βE381A, L, K, and R, and γR242L and E mutations perturbed enzyme assembly and stability to varying degrees. These results provide functional evidence that the β380DELSEED386 segment and its interactions with the γ-subunit are involved in the mechanism of coupling.


1996 ◽  
Vol 154 (2) ◽  
pp. 107-111 ◽  
Author(s):  
Immaculada Martin ◽  
Josep A. Villena ◽  
Marta Giralt ◽  
Roser Iglesias ◽  
Teresa Mampel ◽  
...  

2000 ◽  
Vol 20 (9) ◽  
pp. 3125-3136 ◽  
Author(s):  
Atan Gross ◽  
Kirsten Pilcher ◽  
Elizabeth Blachly-Dyson ◽  
Emy Basso ◽  
Jennifer Jockel ◽  
...  

ABSTRACT The BCL-2 family includes both proapoptotic (e.g., BAX and BAK) and antiapoptotic (e.g., BCL-2 and BCL-XL) molecules. The cell death-regulating activity of BCL-2 members appears to depend on their ability to modulate mitochondrial function, which may include regulation of the mitochondrial permeability transition pore (PTP). We examined the function of BAX and BCL-XL using genetic and biochemical approaches in budding yeast because studies with yeast suggest that BCL-2 family members act upon highly conserved mitochondrial components. In this study we found that in wild-type yeast, BAX induced hyperpolarization of mitochondria, production of reactive oxygen species, growth arrest, and cell death; however, cytochrome c was not released detectably despite the induction of mitochondrial dysfunction. Coexpression of BCL-XL prevented all BAX-mediated responses. We also assessed the function of BCL-XL and BAX in the same strain of Saccharomyces cerevisiae with deletions of selected mitochondrial proteins that have been implicated in the function of BCL-2 family members. BAX-induced growth arrest was independent of the tested mitochondrial components, including voltage-dependent anion channel (VDAC), the catalytic β subunit or the δ subunit of the F0F1-ATP synthase, mitochondrial cyclophilin, cytochrome c, and proteins encoded by the mitochondrial genome as revealed by [rho 0] cells. In contrast, actual cell killing was dependent upon select mitochondrial components including the β subunit of ATP synthase and mitochondrial genome-encoded proteins but not VDAC. The BCL-XL protection from either BAX-induced growth arrest or cell killing proved to be independent of mitochondrial components. Thus, BAX induces two cellular processes in yeast which can each be abrogated by BCL-XL: cell arrest, which does not require aspects of mitochondrial biochemistry, and cell killing, which does.


2007 ◽  
Vol 144 (2) ◽  
pp. 1190-1199 ◽  
Author(s):  
Robert van Lis ◽  
Guillermo Mendoza-Hernández ◽  
Georg Groth ◽  
Ariane Atteia

1997 ◽  
Vol 243 (1-2) ◽  
pp. 336-343 ◽  
Author(s):  
Carsten Etzold ◽  
Gabriele Deckers-Hebestreit ◽  
Karlheinz Altendorf

2005 ◽  
Vol 1708 (2) ◽  
pp. 143-153 ◽  
Author(s):  
Stefan Steigmiller ◽  
Michael Börsch ◽  
Peter Gräber ◽  
Martina Huber

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