Discussion of all aspects of biological molecules, biochemical processes and laboratory procedures in the field.
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Sorry I'm asking such a basic question, but I can't seem to find the answer on my own.
All of the books I've read say that ATP provides the energy to power the cell. I can grasp that as an exothermic reaction, it can be coupled with endothermic reactions to make it exothermic overall, however, I'm not sure how this would apply to its use in powering proteins, like myosin or protein pumps. Can someone explain how ATP could "power" a protein?
I think I understand it a little bit better, but, thinking about it again, changing the conformation of a protein requires some sort of power source, still. Unless that's what you meant by stimulus? How would the binding of a cofactor or ATP hydrolysis supply the energy needed for the conformation change?
I thought maybe it would be the bond energy, but then it wouldn't make sense for both forming and breaking bonds to work.
What do you exactly mean by "how would binding of cofactor/ATP supply energy?" Are you saying
[* that you doubt ATP binding or Cofactor binding has enough energy?]
[* or you cannot see the transition of chemical energy of bond hydrolysis to mechanical energy required in conformation change?][/list]
If it's the first question - its pretty simple. Look at the numbers. But that won't be convincing because, in the end its just numbers, no realization!
If it's the second, I got a vague explanation as to how it might occur. When ATP/cofactor or something binds to a site, it is changing the angles between the bonds of the associated atoms. Every atom changes its bond angles and this might lead to drastic changes in conformation. Remember - I am not sure about this - just getting you started. Now that you make me think of it, I feel it's interesting. (This'd have been obvious if ATP binded to the protein's atoms through covalent bonds, then hybridization changes and the bond angles change. Think of it like that game Jenga where one critical block that's removed is all it takes to collapse the structure. But then, I don't know if ATP binds that way.)
Don't think qualitatively. Think quantitatively. If you make a profit and a loss in subsequent months, are you back to square one? NO! Not necessarily. What if you score 10 grands one month and lose a measly 200$ the next? You're still profiting. That's what's happening here as well!
ATP can change the enzymatic conformation by adding a phosphate group to it. This changes the conformation because the phosphate group is polar and is negatively charged. If you know your basic high school knowledge, enzymatic shape is determined by the specific placement of specific amino acids because the side chains (R-groups) each have different properties that can affect the whole shape. A single phosphate group can dramatically alter the enzymatic shape through its intermolecular interactions with the amino acids and can activate or inhibit the enzyme.
Science is truly the understanding of the amazing works of God.
6 posts • Page 1 of 1
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