m4p5

These flashcards cover key concepts regarding protein purification techniques and the structure and function of hemoglobin and myoglobin, as discussed in Module 4 of the lecture.

What are the three primary approaches biochemists use to determine protein structures?

X-ray crystallography, nuclear magnetic resonance (NMR) spectroscopy, and cryo-electron microscopy (cryo-EM).

What is the role of proteins in living cells?

Proteins catalyze biochemical reactions, organize cell structures, transport biomolecules, transduce cellular signals, and manage genetic information.

What is the structure of hemoglobin?

Hemoglobin is a tetrameric protein composed of two alpha and two beta subunits.

How does myoglobin differ from hemoglobin?

Myoglobin is a monomeric protein that serves as an oxygen storage protein, while hemoglobin transports oxygen from the lungs to tissues.

What conformational changes occur in hemoglobin upon oxygen binding?

Oxygen binding causes a shift from the T state to the R state, altering the affinity of other subunits for oxygen binding.

What happens to the iron atom in hemoglobin when oxygen binds?

The iron moves into the plane of the heme, resulting in a conformational change of the F helix.

What role do histidine residues play in oxygen transport?

The proximal histidine coordinates with Fe2+, while the distal histidine stabilizes the interaction between O2 and the heme.

What is the significance of the displacement of His F8 in hemoglobin?

It results in a tilt in the F-helix, contributing to the molecular mechanism of oxygen transport.

What coloration changes occur in meat due to hemoglobin?

Fresh meat appears red due to Fe2+ in hemoglobin, while old meat turns brown from oxidized Fe3+.

What are the structural similarities between myoglobin and hemoglobin?

Both consist of eight α helices with a heme molecule, despite low amino acid sequence similarity.