18 Questions
What is the central metal ion in the heme molecule?
Fe2+
What is the function of the heme group in hemoglobin and myoglobin?
To reversibly bind oxygen
What is the prosthetic group tightly bound to hem proteins?
Heme
What is the structure of myoglobin?
A compact molecule with α-helix stretches
What is the function of myoglobin?
To function as a reservoir for oxygen
What is the coordination of the heme Fe++?
One bond to the side chain of a histidine residue and one available to bind oxygen
What is the central element of the porphyrin ring in myoglobin?
Iron
What is the function of the distal histidine in myoglobin?
Helps stabilize the binding of oxygen
What is the structure of hemoglobin A?
Four polypeptide chains: two α chains and two β chains
What is the difference between the T form and the R form of hemoglobin?
T form has low oxygen affinity, R form has high oxygen affinity
What is the significance of the oxygen dissociation curve for myoglobin?
It shows a hyperbolic shape
What is the difference between the oxygen binding affinity of myoglobin and hemoglobin?
Myoglobin has higher oxygen binding affinity than hemoglobin
Which type of bond stabilizes the α-helix?
Intra chain hydrogen bonds
What is the characteristic feature of a β-sheet?
Segments of polypeptide chains running alongside each other
In a β-sheet, what type of bonds are formed between different segments of polypeptide?
Hydrogen bonds
What is the name given to a simple structural motif involving β-sheets?
β-Bend (β-hairpin)
In an antiparallel β-sheet, what is the arrangement of the N-terminal and C-terminal ends of the β-strands?
They are alternating
What is the typical composition of a β-Bend?
Four amino acids, including proline and glycine
Learn about the process of protein folding, including the role of chaperones and the transition from molten globule state to native conformation. Also, discover how proteins can denature and lose their structure. Test your knowledge on protein folding and denaturation.
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