MICR221 Lecture 10 - Bacterial ATP Synthesis and How It Becomes The Newest Target-Space For Antibiotics

Question 1

what 2 processes are tightly coupled in bacteria?

Answer 1

cellular respiration and ATP synthesis

Question 2

what governs all steps of central carbon metabolism, ETC activity and ATP synthesis?

Answer 2

the balance of anabolism:catabolism and proton back pressure

Question 3

what is an uncoupled cell?

Answer 3

a cell that has broken links between central carbon metabolism, ATP synthesis and ETC activity therefore the cell will exhaust energy currencies to try and restore the PMF

Question 4

what is the soluble fraction in the F1Fo-ATPsynthase?

Answer 4

F1 unit

Question 5

what is the F1Fo-ATPsynthase composed of?

Answer 5

composed of 2 major components –> the F1 unit and the Fo unit

Question 6

what is the F1 unit of F1Fo-ATPsynthase?

Answer 6

the unit located in the cytoplasm that binds to ADP+Pi and converts to ATP

Question 7

what is the Fo unit of F1Fo-ATPsynthase?

Answer 7

this unit is the motor and is able to rotate

Question 8

what is the turbine of the F1Fo-ATPsynthase?

Answer 8

the turbine is driven by H+ flow and rotates the central stalk in the F1 unit. This unit is the fraction sensitive to oligomycin

Question 9

what is the relationship of the F1 unit and the Fo unit in the F1Fo-ATPsynthase?

Answer 9

both the F1 and the Fo unit are chemomechanically coupled

Question 10

what are the 2 key subunits of the F1Fo-ATPsynthase?

Answer 10

catalytic subunits and ion-binding subunits

Question 11

what are the 2 catalytic subunits of the F1Fo-ATPsynthase?

Answer 11

beta catalytic subunit

gamma catalytic subunit

Question 12

what is the function of the beta catalytic subunit?

Answer 12

binds ADP + Phosphate –> ATP

Question 13

what is the function of the gamma catalytic subunit?

Answer 13

rotates and induces conformational changes

Question 14

what are the 2 ion-binding subunits of the F1Fo-ATPsynthase?

Answer 14

alpha ion-binding subunit

c ion-binding subunit

Question 15

what is the function of the alpha ion-binding subunit?

Answer 15

takes H+ and passes it to the c subunit

Question 16

what is the function of the c ion-binding subunit?

Answer 16

rotates and releases H+ into the cytoplasm

Question 17

what do the other subunits in general terms have roles in from the F1Fo-ATPsynthase?

Answer 17

other subunits have roles in regulation and complex stability

Question 18

what are the 3 major conformations of the binding change mechanism?

Answer 18

open
loose
tight

Question 19

what is the open conformation of the binding change mechanism?

Answer 19

when nothing is bound

Question 20

what is the loose conformation of the binding change mechanism?

Answer 20

when ADP + Pi is bound

Question 21

what is the tight conformation of the binding change mechanism?

Answer 21

when its closed and forms ATP

Question 22

what are the 3 major steps in rotation?

Answer 22

open –> loose –> tight –> open etc they are 3x 120 degree steps

Question 23

how many substeps may be in the major conformations of the binding change mechanism?

Answer 23

may be 6 or more substeps and this varies between organisms

Question 24

how many H+ protons are used for every 1 ATP made?

Answer 24

3.3 H+ protons are used for every 1 ATP made

Question 25

why are 3.3 H+ protons used for every 1 ATP made?

Answer 25

because the mitochondrial enzyme has 10 c-subunits and this equals 10 H+ protons for a full rotation therefore 3 ATP are produced from 10 H+ protons. However different organisms have different amounts of c subunits varying from anywhere between 2.7-5 H+ protons per ATP

Question 26

when is a sodium-motive force an advantage?

Answer 26

a sodium motive force is an advantage when passive proton leak/loss is high in some anaerobes which occurs in high temps or pH used by some pathogens

Question 27

what is a sodium motive force?

Answer 27

a Na+ coordinated c-ring pocket by glutamate and others

Question 28

what is the difference between a sodium motive force and a proton motive force?

Answer 28

a sodium motive force is an Na+ coordinated c-ring pocket by glutamate and others and a proton motive force is a c-ring of glutamate that binds H+

Question 29

what is a proton motive force?

Answer 29

c-ring of glutamate that binds H+

Question 30

what is fermentation?

Answer 30

the synthesis of ATP exclusively by substrate level phosphorylation that has a lower ATP yield and is used when oxidative phosphorylation is not possible

Question 31

what do most pathogens use?

Answer 31

oxidative phosphorylation

Question 32

why is fermentation a last resort strategy?

Answer 32

because the end products are toxic and must be secreted and is not viable in the long term

Question 33

what is lactic acid fermentation?

Answer 33

the metabolic process by which glucose or other 6 carbon sugars are converted into cellular energy and lactic acid

Question 34

what is homolactic lactic acid fermentation?

Answer 34

only lactate is produced eg yoghurt

Question 35

what is heterolactic acid fermentation?

Answer 35

lactate, ethanol and acetate are produced e.g sauerkraut

Question 36

what is mixed acid fermentation?

Answer 36

end products vary according to environmental conditions but still undergoes the same oxidative phosphorylation linked steps

Question 37

what is alcohol fermentation?

Answer 37

an interest in the production of bioethanol