Unit 1: Proteomics & Protein Structure 3 Flashcards
Binding to Ligands
A ligand is a
substance that binds to proteins
Binding sites on a protein will be complementary to the
ligand
What is a nucleosome?
DNA wrapped around eight histones
What is a histone?
Eight proteins surround by a nucleosome
To maximise space how are nucelosomes arranged?
Stacked on top of each other
Some proteins binding sites are specific to cetrain sequences of DNA as a result
when bound can stimulate or inhibit transcription
When a ligand binds to a protein the
conformation changes
A conformational change in a protein can either
activate or deactivate it
Describe induced fit in enzymes
When the correct substrate binds to the enzyme a temporary change in the conformation occurs increasing the binding and interaction with the substrate
An allosteric enzyme is an enzyme that can
have its activity altered by a ligand called a modulator
In allosteric enzymes, where to modulators bind?
At secondary binding sites
Negative modulators reduce the enzyme’s
affinity for the substrate
Positive modulators increase the enzyme’s affinity for the
substrate by altering the conformation of the active site so it fits the substrate better
End product inhibition is an example of
negative feedback control
Describe end product inhibiton
The final product of a series of enzyme reactions interacts with an allosteric enzyme inhibiting it and thus ending the reaction.
