a vacuole. It is not a problem. A bubble within a larger bubble, the cell. Perhaps a storage place for fats. In the Victorian era, such dismissive behavior was forgivable. Now we know better. Who would have thought that turbocharged Wankel engines would coat the membranes of vacuoles and adjust the acidity inside to tightly regulated specifications?
Our popular ATP synthase videoillustrates a type of rotational motor in the cell: the F-type ATPase. These molecular marvels are one-tenth the size of the bacterial flagellum, but spin at speeds of up to 42,000 rpm. They absorb protons and produce ATP molecules. Another type of rotary motor, the vacuolar ATPase (V-ATPase), works in a similar way, but in reverse. It releases a "coin" of ATP to pump protons against the concentration gradient into the vacuoles, regulating their acidity. V-ATPases are essential organelles in all three kingdoms of life and are involved in many cellular functions. A 2013 article inBioArquitecturashe presents:
Vacuolar or V-type ATPases are more distantly related rotary motors that function in reverse as ATP synthases. use of energy from ATP hydrolysis,They pump cations through membranes, much like artificial rotary pumps.are type V ATPasesImportant for the acidification of intracellular compartments.and generate transmembrane electrochemical potential gradientsThey provide the energy for SiM or antiporters to actively transport ions and molecules across membranes.It has been reported that they resist itHundredfold differences in proton concentrationbetween the cytosol and the intracellular compartment. Again, there are three versions; HeEukaryotesATPase type V and two simpler onesbacterialATPase type V and thesheetsA-type ATPases that are structurally indistinguishable and therefore often grouped together as "A-type ATPases/synthases". [emphasis added.](Video) Only flying C-123K Provider almost crashes at Geneseo New York airshow #thunderpig #c123k #save
Your life depends on these engines.WikipediaName some of the roles they play in your body:
V-ATPases have been foundin the membranes of many organelles, ifendosomes, lysosomes and secretory vesicles., where do you playa variety of roles critical to the positionthese organelles. For example, the proton gradient generated by V-ATPases travels through the vacuole membrane of yeastcalciuminnameinto the vacuole via an H+/Ca2+ antiporter system (Ohya, 1991). Insynaptic transmission in neuronal cellsV-ATPase acidifies synaptic vesicles. Noradrenaline enters the vesicles. by V-ATPase.
V-ATPase syndIt is also found in the plasma membranes of various cells.than the intercalated cells of theKidneys,Osteoclasten(bone resorption cells),macrophages, neutrophils, sperm, insect midgut cells and certain tumor cells. Plasma membrane V-ATPases are involved in processes such aspH homeostasis, coupled transport.and tumor metastases. V-ATPases in the acrosomal membrane ofSpermacidify the acrosome.This acidification activates the proteases needed to cross the egg's plasma membrane.. V-ATPase in derOsteolastoThe plasma membrane pumps protons to the bone surfacenecessary for bone loss. In the intercalated cells of theKidneysV-ATPases pump protons into the urine, allowing bicarbonate to be reabsorbed into the blood.
(We don't consider tumor metastases a "function," but rather a dysfunction.) But think about it; Without a V-ATPase, which allows a protease to cross the robust egg membrane, you would never have been born. Your kidneys need V-ATPases. Your bones need them. Your immune system and nervous system need them. Are you starting to appreciate these engines?
Anew roleNatureHe took a closer look at the V-ATPase in yeast cells. Using cryo-electron microscopy, three Toronto researchers were able to look at the components of these molecular motors in unprecedented detail and deduce for the first time how they move and interact during operation. Here's how they compared V-ATPase to the better known F-type ATP synthase:
The eukaryotic V-ATPase isthe most complex rotary ATPase: Hatthree peripheral stems, a heterooligomeric proton-conducting proteolipid ring,several subunits not found in other rotary ATPases, forksregulatedby reversible dissociation of their catalytic and proton conducting regions.
V-ATPase has two additional stators that look like buttresses that hold the whole machine in place while it is running. The V-shaped carousel0The subunit with its ten ring segments "acts like a ten-step motor," he says. And because it has to push protons against a steep concentration gradient in the organelle, the machine is hermetically sealed against leakage.
The V-ATPase illustrations in the article are beautiful. The authors have also included three video clips: one of the actual enginesand the Ortand two animations showing how the parts interact. Note the machine metaphors in this quote:
The E and G subunits of the peripheral stems undergo bending motion along their elongated vertebral region.reminiscent of the action of a cantilevered spring(Fig. 4c, zoomed data, Fig. 6g-i and Supplementary Videos 2 and 3). The N-terminal domain of the α subunit oscillates parallel to the membrane and moves towards and away from the axis of rotation of the rotor.like the arm of a record player.
It has long been a mystery why the top and bottom of the engine are not completely connected. The outer V1For example, one part digests three ATP per cycle. into the V0The part that pumps protons consists of ten units. This creates a non-integer ratio of 3:10. Is that a sin? Will this cause slippage in the machine? Now there seems to be a reason for that.
The resulting array of structures reveals ten proteolipid subunits in the C ring, yielding an ATP:H+ ratio for V-ATPase proton pumps of 3:10 and revealing β helices. long and steeply inclined transmembrane cells in the α subunit interacting with the C ring. The three different cards show theConformational changes arising from the coupling of rotation in the soluble catalytic region of mismatched symmetry to the membrane-bound proton translocation region. Nearly all subunits of the enzyme undergo conformational changes when transitioning between these three rotational states.The structures of these states provide direct evidence that deformation during rotation allows smooth force transfer via rotational ATPases.
While still under investigation, the mismatch does add some efficiency, perhaps keeping the engine running. For this function, the conformational changes are coordinated:
Overall, the structures presented here demonstrate this in the V-ATPaseBoth the rotor and stator of the motor undergo coordinated conformational changes.This combination offlexibilityJstiffnessesprobably a key attribute for the functionvonthese highly efficient macromolecular machines.
And now the Darwinists. Here's all they have to say about evolution:
The presence of these conformational changes is not apparent upon inspection of the crystal structures of the individual subunits. However, if you watch it as a movie,Each subunit seems to have evolved to perform these movements.
This should save them trouble with the censors who might wonder if they are secretly proponents of intelligent design.
Cognitive dissonance between design.Evidenceand the evolutionaryTo believeIt gets even clearer inBioArquitecturapiece mentioned above. There, four Australian researchers are trying to demonstrate the similarities between rotating ATPases and human-designed motors. They talk about the different types of 'fuels' used by engines and how lipids act as 'motor oil' for 'lubrication'. They compare the placement angle of several ATPases to the angle of a V8 engine. They talk about turbines, stepper motors, gear ratios, compressors, crankshafts, brakes, pawls, frames, torsion bars, pushrods and more! It is awesome. The stage is set for a design conclusion! Then comes the conclusion:
Molecular machines, such as the rotating ATPases described here, appear to have much in common with man-made machines.. However,Analogies are only valid up to a point.and are for the most part not fully understood.What is clear is that billions of years of evolution have resulted in biological engines that are unsurpassed in terms of efficiency, adaptability to their environment and durability.
To use Charlie Brown's most common word: "AAAAAGGGGHHH!"
The evolution of ATP synthase is thought to have been modular whereby two functionally independent subunits became associated and gained new functionality.What is an example of ATP synthase? ›
The ATP Synthase
Most members of the group use H+ as the coupling ion (the Propionigenium modestum enzyme is an example of the few ATP synthases that can use Na+ as the physiological coupling ion).
ATP synthase is the enzyme that makes ATP molecules. It is a multi-part complex that straddles the inner membrane of mitochondria, the energy factories in cells. The enzyme complex interacts with fatty molecules in the mitochondrial inner membrane, creating a curvature that is required to produce ATP more efficiently.Does E coli have ATP synthase? ›
Escherichia coli robustly expresses ATP synthase at growth rate‐maximizing concentrations.