Structure of the γ-ε complex of cyanobacterial F1-ATPase reveals a suppression mechanism of theγ subunit on ATP-hydrolysis in phototrophs
| Autor: | Georg Groth, Toru Hisabori, Eiki Yamashita, Shinya Katayama, Ei-Ichiro Sunamura, Satoshi Murakami, Satoshi Hara, Kumiko Kondo |
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| Rok vydání: | 2018 |
| Předmět: |
0301 basic medicine
chemistry.chemical_classification Enzyme complex Phototroph ATP synthase biology Hydrogen bond Chemistry Protein subunit ATPase Cell Biology Biochemistry Amino acid 03 medical and health sciences 030104 developmental biology ATP hydrolysis biology.protein Biophysics Molecular Biology |
| Zdroj: | Biochemical Journal. 475:2925-2939 |
| ISSN: | 1470-8728 0264-6021 |
| DOI: | 10.1042/bcj20180481 |
| Popis: | F 1 -ATPase forms the membrane-associated segment of F 0 F 1 -ATP synthase — the fundamental enzyme complex in cellular bioenergetics for ATP hydrolysis and synthesis. Here, we report a crystal structure of the central F 1 subcomplex, consisting of the rotary shaft γ subunit and the inhibitory e subunit, from the photosynthetic cyanobacterium Thermosynechococcus elongatus BP-1, at 1.98 A resolution. In contrast with their homologous bacterial and mitochondrial counterparts, the γ subunits of photosynthetic organisms harbour a unique insertion of 35–40 amino acids. Our structural data reveal that this region forms a β-hairpin structure along the central stalk. We identified numerous critical hydrogen bonds and electrostatic interactions between residues in the hairpin and the rest of the γ subunit. To elaborate the critical function of this β-hairpin in inhibiting ATP hydrolysis, the corresponding domain was deleted in the cyanobacterial F 1 subcomplex. Biochemical analyses of the corresponding α 3 β 3 γ complex confirm that the clinch of the hairpin structure plays a critical role and accounts for a significant interaction in the α 3 β 3 complex to induce ADP inhibition during ATP hydrolysis. In addition, we found that truncating the β-hairpin insertion structure resulted in a marked impairment of the interaction with the e subunit, which binds to the opposite side of the γ subunit from the β-hairpin structure. Combined with structural analyses, our work provides experimental evidence supporting the molecular principle of how the insertion region of the γ subunit suppresses F 1 rotation during ATP hydrolysis. |
| Databáze: | OpenAIRE |
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