Term
| coupled with electron transport: chemiosmotic synthesis |
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Definition
protons are pumped from matrix to intermembrane space across inner membrane.
proton gradient has 2 components:
chemical (pH)
electrical (deltaV)
Proton Motive Force makes protons flow back, powering ATP synthesis |
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Term
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Definition
subunits:F0 (proton conducting) inside membrane and F1 (catalytic) on surface of membrane.
Fo and F1 are connected by central γε stalk and by an exterior column “b2 subunit”
rotor: moving unit, consists of c ring and γε stalk
stator: rest of molecule |
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Term
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Definition
Integral membrane proton channel:
- ring of 10-14 “c-subunits” which form proton channel
- “a subunit” binds to outside of ring |
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Term
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Definition
-α3β3 hexamer binds nucleotides, β subunit synthesizes ATP
-β subunits synthesize ATP |
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Term
| pentacovalent intermediate |
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Definition
| between ADP and ATP. ATP synthase stabilizes the intermediate by binding ADP and Pi at β subunit |
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Term
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Definition
Tight (T): Binds very strongly to ATP (drives ATP synthesis by binding energy)
-Loose (L): Binds ADP and Pi and traps them in the active site
-Open(O): lowest affinity, releases bound ATP |
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Term
| interconversion of beta subunit binding states |
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Definition
3H+ moving through the c-ring into matrix drives 120o rotation of the γ subunit
This causes a coordinated change in the conformation of the three β subunits
T →O synthesized ATP is released
- L → T ADP + Pi is converted to ATP
- O→ L ADP + Pi is trapped in active site
For a ring of 10 c subunits, ~3 H+ pumped per 120o rotation needed to synthesize and release 1 ATP |
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