Abstract
F1-ATPase is an ATP-driven rotary molecular motor in which the central γ-subunit rotates inside the cylinder made of α 3β3 subunits. The amino and carboxy termini of the γ-subunit form the axle, an α-helical coiled coil that deeply penetrates the stator cylinder. We previously truncated the axle step by step, starting with the longer carboxy terminus and then cutting both termini at the same levels, resulting in a slower yet considerably powerful rotation. Here we examine the role of each helix by truncating only the carboxy terminus by 25-40 amino-acid residues. Longer truncation impaired the stability of the motor complex severely: 40 deletions failed to yield rotating the complex. Up to 36 deletions, however, the mutants produced an apparent torque at nearly half of the wild-type torque, independent of truncation length. Time-averaged rotary speeds were low because of load-dependent stumbling at 120° intervals, even with saturating ATP. Comparison with our previous work indicates that half the normal torque is produced at the orifice of the stator. The very tip of the carboxy terminus adds the other half, whereas neither helix in the middle of the axle contributes much to torque generation and the rapid progress of catalysis. None of the residues of the entire axle played a specific decisive role in rotation.
| Original language | English |
|---|---|
| Pages (from-to) | 4837-4844 |
| Number of pages | 8 |
| Journal | Biophysical Journal |
| Volume | 95 |
| Issue number | 10 |
| DOIs | |
| Publication status | Published - 2008 Nov 15 |
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ASJC Scopus subject areas
- Biophysics
Cite this
Neither helix in the coiled coil region of the axle of F1-ATPase plays a significant role in torque production. / Hossain, Mohammad Delawar; Furuike, Shou; Maki, Yasushi; Adachi, Kengo; Suzuki, Toshiharu; Kohori, Ayako; Itoh, Hiroyasu; Yoshida, Masasuke; Kinosita, Kazuhiko.
In: Biophysical Journal, Vol. 95, No. 10, 15.11.2008, p. 4837-4844.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Neither helix in the coiled coil region of the axle of F1-ATPase plays a significant role in torque production
AU - Hossain, Mohammad Delawar
AU - Furuike, Shou
AU - Maki, Yasushi
AU - Adachi, Kengo
AU - Suzuki, Toshiharu
AU - Kohori, Ayako
AU - Itoh, Hiroyasu
AU - Yoshida, Masasuke
AU - Kinosita, Kazuhiko
PY - 2008/11/15
Y1 - 2008/11/15
N2 - F1-ATPase is an ATP-driven rotary molecular motor in which the central γ-subunit rotates inside the cylinder made of α 3β3 subunits. The amino and carboxy termini of the γ-subunit form the axle, an α-helical coiled coil that deeply penetrates the stator cylinder. We previously truncated the axle step by step, starting with the longer carboxy terminus and then cutting both termini at the same levels, resulting in a slower yet considerably powerful rotation. Here we examine the role of each helix by truncating only the carboxy terminus by 25-40 amino-acid residues. Longer truncation impaired the stability of the motor complex severely: 40 deletions failed to yield rotating the complex. Up to 36 deletions, however, the mutants produced an apparent torque at nearly half of the wild-type torque, independent of truncation length. Time-averaged rotary speeds were low because of load-dependent stumbling at 120° intervals, even with saturating ATP. Comparison with our previous work indicates that half the normal torque is produced at the orifice of the stator. The very tip of the carboxy terminus adds the other half, whereas neither helix in the middle of the axle contributes much to torque generation and the rapid progress of catalysis. None of the residues of the entire axle played a specific decisive role in rotation.
AB - F1-ATPase is an ATP-driven rotary molecular motor in which the central γ-subunit rotates inside the cylinder made of α 3β3 subunits. The amino and carboxy termini of the γ-subunit form the axle, an α-helical coiled coil that deeply penetrates the stator cylinder. We previously truncated the axle step by step, starting with the longer carboxy terminus and then cutting both termini at the same levels, resulting in a slower yet considerably powerful rotation. Here we examine the role of each helix by truncating only the carboxy terminus by 25-40 amino-acid residues. Longer truncation impaired the stability of the motor complex severely: 40 deletions failed to yield rotating the complex. Up to 36 deletions, however, the mutants produced an apparent torque at nearly half of the wild-type torque, independent of truncation length. Time-averaged rotary speeds were low because of load-dependent stumbling at 120° intervals, even with saturating ATP. Comparison with our previous work indicates that half the normal torque is produced at the orifice of the stator. The very tip of the carboxy terminus adds the other half, whereas neither helix in the middle of the axle contributes much to torque generation and the rapid progress of catalysis. None of the residues of the entire axle played a specific decisive role in rotation.
UR - http://www.scopus.com/inward/record.url?scp=58149280492&partnerID=8YFLogxK
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U2 - 10.1529/biophysj.108.140061
DO - 10.1529/biophysj.108.140061
M3 - Article
C2 - 18708468
AN - SCOPUS:58149280492
VL - 95
SP - 4837
EP - 4844
JO - Biophysical Journal
JF - Biophysical Journal
SN - 0006-3495
IS - 10
ER -