ATP synthase Structure and General Info

What does the transfer of protons (“pumped out”) from the matrix generate

proton-motive gradient

high proton concentration in intermembrane space

low proton concentration in mitochondrial matrix

What drives ATP synthesis

the flow of protons back to the matrix side through ATP synthase

Where is the F0 subunit found and what property does it have

hydrophobic- found in inner mitochondrial membrane

what makes up the F0 subunit

c-subunits
a-subunit

two b peptides

what do c-subunits form

make the proton channel component consisting of a ring of 10-14 c-subunits

c-subunit composition

two alpha-helices and an aspartic acid residue (Asp 61)

what are the c-subunits connected to

connected to gamma and epsilon subunits of F1

a subunit location

located just outside the c-subunit ring

a subunit composition

two, hydrophilic, half-channels; one open to the cytosol ("entry") and the other open to the matrix ("exit”)

what do the two b peptides connect

connect the F0 and F1 subunits

what is the purpose of the b peptides

together with the delta subunit of the F1 subunit, they prevent the F1 subunit from rotating

Where is the F1 subunit found and what property does it have

hydrophilic- found in the mitochondrial matrix

What is F1’s diameter

85 angstroms

F1 composition (subunits in F1)

alpha3

beta3

gamma

delta

epsilon

what do alpha3 and beta3 subunits form

alpha3beta3 hexameric ring consisting of alternating alpha and beta subunits with a gamma-subunit core

What part of the F1 subunit connects it to the F0 subunit

central stalk consisting of gamma and epsilon subunits connects the F1 subunit to the F0 subunit at the c-subunit ring

What do the beta-subunits interact with

each beta-subunit interacts with a different part (“face”) of the gamma-subunit core

How to estimate number of protons needed to make one molecule

Consider number of c-subunits in the c-ring

(e.g. yeast-

10 c-subunits in c-ring

one rotation of c-ring requires 10 protons

one rotation of gamma-subunit makes 3 ATP

10 protons to make 3 ATP = 3.33 protons/ATP)