Protein Structure Ligand Binding And Conformational Change- Ligand Binding Changes The Conformation Of A Protein A Flashcards
What is a ligand?
A substance that can bind to a protein
What allows ligands to bind?
The R groups not involved in protein folding
What do binding sites have that the ligands are binding to have?
Complementary shape and chemistry to the ligand
As a ligand binds to a protein-binding site what changes?
The conformation of the protein
What does the conformational change when a ligand binds the protein cause?
A functional change in the protein
Where do allosteric interactions occur?
Between spatially distinct sites
What happens when a substrate molecule binds to an active sites of an allosteric enzyme?
The affinity of other active sites for binding of subsequent substrate molecules is increased.
How is the binding of substrates to allosteric enzymes causing increased affinity for other substrates on other active sites biologically important?
Because the activity of allosteric enzymes can vary greatly with small changes in substrate concentration
What do many allosteric proteins consist of?
Multiple subunits (quaternary structure)
What do allosteric proteins with multiple subunits show?
Co-operativity in binding in which changes in binding at one subunit alter the affinity of the remaining subunits
What do allosteric enzymes contain?
A second type of site called an allosteric site
What does a modulator do?
It regulates the activity of the enzyme when they bind to the allosteric site
What happens after the binding of a modulator on an allosteric site?
The conformation of the enzyme changes and this alters the affinity of the active site for the substrate
What do positive modulators do?
They increase the enzyme’s affinity for the substrate
What do negative modulators do?
They decrease the enzyme’s affinity
