Lecture 5 - Exam 1 Flashcards
What does X-ray crystallography do?
What was it used in solving?
Create crystallized structures with ordered molecule and shoot an X ray beam through this, the X rays will be diffracted. Based off diffraction patterns, can determine what molecule you are looking at.
Used in solving the 3-D protein structure
Who helped solved the 3-D protein structure?
John Kendrew & Max Perutz
Used Sperm Whale Myoglobin
*Computer modeling too
Local amino acid sequences which form stable interactions will serve as…?
Nucleation points in the folding process.
What is a fundamental role of proteins?
To act as enzymes.
What are enzymes?
Enzymes are catalysts that increase the rate of all chemical reactions in cells. Without enzymes, most biochemical reactions are so slow that they would not occur.
What are the fundamental properties of enzymes?
Increase rate of chemical reactions without themselves being consumed or permanently altered.
Increase reaction rates without altering the chemical equilibrium between reactants and products.
How is equilibrium determined?
Equilibrium is determined by the final energy states of substrate and product.
The substrate must first be converted to a higher energy state, the transition state.
Energy required to reach the transition state =
activation energy.
Enzymes reduce the activation energy.
Enzymes must bind their ______ to form _________.
substrates ; enzyme-substrate complex (ES)
Where does the substrate bind?
The substrate is converted to ______ while bound.
Active site
The substrate is converted to product while bound to the active site, then released.
The enzymes brings the substrates together in proper orientation to _____.
Favor the transition state.
Enzymes also accelerate reactions by _________.
Altering the conformation of substrates to approach the transition state.
The stress produced by distortion of the substrate further lowers the transition state by weakening critical bonds in the protein substrate.
What is the lock-and-key model?
The substrate fits precisely into the active site.
What is induced fit?
Conformation of both enzyme and substrate is modified.
Who discovered Chaperons?
F. Ritossa when a lab worker accidentally boosted the incubation temperature of Drosophila.
When examining the chromosomes, Ritossa found a “puffing pattern” that indicated elevated gene transcription of an unknown protein.