Glycogen, TCA Cycle and Mitochondria (Lecture 15) Flashcards
ATPase
F1 mitochondrial matrix (water soluble)
Fo is in the inter membrane space
is uses the PMF to bower the rotation of ATP synthase
what does the rotation of ATP synthase do?
causes a conformational change in the protein to initiate the ATP synths in the matrix
what connects F1 Fo subunits?
the epsilon protein stalk
F1
pseudo 3 fold symmetry
beta subunit is responsible for catalyzing synthesis of ATP
at any given time, one subunit is making ATP
( empty, bound to ADP, bound to ATP)
Fo
in the membrane
rotates
contain a transmembrane ring, with 8 subunits
number of protons translocated for every ATP synthesized is fixed (determined by number of c subunits)
since 3 catalytic sites are present in F1, the number of protons translocated per every ATP molecule is = c subunits /3
F1 beta subunit conformations
O- open, not bound
L-loose, binds ligand (ADP + Pi) but not active
T-catalytically active to make ATP
F1 reaction sequence
ATP generated in T site, ADP binds to loose site
energy dependent conformational change will convert L to T , T to O, O to L
the o site has ATP, which is released, the T site bound to ADP will make ATO and the loose site will eventually bind to ADP ligand
free energy provided by proton motive force facilitates
the release of the newly synthesized ATP
it drives the T to O transition
steps of the ATPase PMF generation
a proton will enter the channel and bind to a c subunit in the o c-ring rover
the c subunit undergoes a conformational change to pushes against the previous subunit to rotate the Fo ring (counter clockwise) to allow another proton to enter
rotation of Fo until H+ reaches the 2nd hydrophilic channel and the proton is released into the cytoplasm
how are the beta subunits of F1 subjected to conformational changes?
rotation of the Fo ring, will rotate the epsilon and gamma protein stalks, thus causing conformational changes
uncoupling of mitochondria will promote:
over heating
wright loss
increased flux of the ETC
lean individuals have ___ brow n adipose tissue
more down adipose activity
this is because uncoupling protein 1 (UPC1) is found in this tissue
UPC1 mechanism
UPC1 is activated by norepinephrine, where it binds to the receptor and promote the generation of cAMP via ADC
cAMP will then activate PKA allosterically
PKA will phosphorylate hormone sensitive lipase
active hormone sensitive lipase will catalyze the release of fatty acids from stored fat
these fatty acids can enter the m mitochondria to fuel the CAC and bind to UPC1 and activate it
