Academic Journal
Mutations on the N-Terminal Edge of the DELSEED Loop in either the α or β Subunit of the Mitochondrial F 1 -ATPase Enhance ATP Hydrolysis in the Absence of the Central γ Rotor
| العنوان: | Mutations on the N-Terminal Edge of the DELSEED Loop in either the α or β Subunit of the Mitochondrial F 1 -ATPase Enhance ATP Hydrolysis in the Absence of the Central γ Rotor |
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| المؤلفون: | La, Thuy, Clark-Walker, George Desmond, Wang, Xiaowen, Wilkens, Stephan, Chen, Xin Jie |
| المصدر: | Eukaryotic Cell ; volume 12, issue 11, page 1451-1461 ; ISSN 1535-9778 1535-9786 |
| بيانات النشر: | American Society for Microbiology |
| سنة النشر: | 2013 |
| الوصف: | F 1 -ATPase is a rotary molecular machine with a subunit stoichiometry of α 3 β 3 γ 1 δ 1 ε 1 . It has a robust ATP-hydrolyzing activity due to effective cooperativity between the three catalytic sites. It is believed that the central γ rotor dictates the sequential conformational changes to the catalytic sites in the α 3 β 3 core to achieve cooperativity. However, recent studies of the thermophilic Bacillus PS3 F 1 -ATPase have suggested that the α 3 β 3 core can intrinsically undergo unidirectional cooperative catalysis (T. Uchihashi et al., Science 333:755-758, 2011). The mechanism of this γ-independent ATP-hydrolyzing mode is unclear. Here, a unique genetic screen allowed us to identify specific mutations in the α and β subunits that stimulate ATP hydrolysis by the mitochondrial F 1 -ATPase in the absence of γ. We found that the F446I mutation in the α subunit and G419D mutation in the β subunit suppress cell death by the loss of mitochondrial DNA (ρ o ) in a Kluyveromyces lactis mutant lacking γ. In organello ATPase assays showed that the mutant but not the wild-type γ-less F 1 complexes retained 21.7 to 44.6% of the native F 1 -ATPase activity. The γ-less F 1 subcomplex was assembled but was structurally and functionally labile in vitro . Phe446 in the α subunit and Gly419 in the β subunit are located on the N-terminal edge of the DELSEED loops in both subunits. Mutations in these two sites likely enhance the transmission of catalytically required conformational changes to an adjacent α or β subunit, thereby allowing robust ATP hydrolysis and cell survival under ρ o conditions. This work may help our understanding of the structural elements required for ATP hydrolysis by the α 3 β 3 subcomplex. |
| نوع الوثيقة: | article in journal/newspaper |
| اللغة: | English |
| DOI: | 10.1128/ec.00177-13 |
| DOI: | 10.1128/EC.00177-13 |
| الاتاحة: | http://dx.doi.org/10.1128/ec.00177-13 https://journals.asm.org/doi/pdf/10.1128/EC.00177-13 |
| Rights: | https://journals.asm.org/non-commercial-tdm-license |
| رقم الانضمام: | edsbas.C786F95B |
| قاعدة البيانات: | BASE |
| DOI: | 10.1128/ec.00177-13 |
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