MICR221 Lecture 10 - Bacterial ATP Synthesis and How It Becomes The Newest Target-Space For Antibiotics Flashcards
what 2 processes are tightly coupled in bacteria?
cellular respiration and ATP synthesis
what governs all steps of central carbon metabolism, ETC activity and ATP synthesis?
the balance of anabolism:catabolism and proton back pressure
what is an uncoupled cell?
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
what is the soluble fraction in the F1Fo-ATPsynthase?
F1 unit
what is the F1Fo-ATPsynthase composed of?
composed of 2 major components –> the F1 unit and the Fo unit
what is the F1 unit of F1Fo-ATPsynthase?
the unit located in the cytoplasm that binds to ADP+Pi and converts to ATP
what is the Fo unit of F1Fo-ATPsynthase?
this unit is the motor and is able to rotate
what is the turbine of the F1Fo-ATPsynthase?
the turbine is driven by H+ flow and rotates the central stalk in the F1 unit. This unit is the fraction sensitive to oligomycin
what is the relationship of the F1 unit and the Fo unit in the F1Fo-ATPsynthase?
both the F1 and the Fo unit are chemomechanically coupled
what are the 2 key subunits of the F1Fo-ATPsynthase?
catalytic subunits and ion-binding subunits
what are the 2 catalytic subunits of the F1Fo-ATPsynthase?
beta catalytic subunit
gamma catalytic subunit
what is the function of the beta catalytic subunit?
binds ADP + Phosphate –> ATP
what is the function of the gamma catalytic subunit?
rotates and induces conformational changes
what are the 2 ion-binding subunits of the F1Fo-ATPsynthase?
alpha ion-binding subunit
c ion-binding subunit
what is the function of the alpha ion-binding subunit?
takes H+ and passes it to the c subunit
what is the function of the c ion-binding subunit?
rotates and releases H+ into the cytoplasm
what do the other subunits in general terms have roles in from the F1Fo-ATPsynthase?
other subunits have roles in regulation and complex stability
what are the 3 major conformations of the binding change mechanism?
open
loose
tight
what is the open conformation of the binding change mechanism?
when nothing is bound
what is the loose conformation of the binding change mechanism?
when ADP + Pi is bound
what is the tight conformation of the binding change mechanism?
when its closed and forms ATP
what are the 3 major steps in rotation?
open –> loose –> tight –> open etc they are 3x 120 degree steps
how many substeps may be in the major conformations of the binding change mechanism?
may be 6 or more substeps and this varies between organisms
how many H+ protons are used for every 1 ATP made?
3.3 H+ protons are used for every 1 ATP made
why are 3.3 H+ protons used for every 1 ATP made?
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
when is a sodium-motive force an advantage?
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
what is a sodium motive force?
a Na+ coordinated c-ring pocket by glutamate and others
what is the difference between a sodium motive force and a proton motive force?
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+
what is a proton motive force?
c-ring of glutamate that binds H+
what is fermentation?
the synthesis of ATP exclusively by substrate level phosphorylation that has a lower ATP yield and is used when oxidative phosphorylation is not possible
what do most pathogens use?
oxidative phosphorylation
why is fermentation a last resort strategy?
because the end products are toxic and must be secreted and is not viable in the long term
what is lactic acid fermentation?
the metabolic process by which glucose or other 6 carbon sugars are converted into cellular energy and lactic acid
what is homolactic lactic acid fermentation?
only lactate is produced eg yoghurt
what is heterolactic acid fermentation?
lactate, ethanol and acetate are produced e.g sauerkraut
what is mixed acid fermentation?
end products vary according to environmental conditions but still undergoes the same oxidative phosphorylation linked steps
what is alcohol fermentation?
an interest in the production of bioethanol
