Protein Structure and Function

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What percentage of the lens is composed of protein at the molecular level?

95%

80%

90% (correct)

70%

What is the primary function of alpha-crystallin in the lens?

To facilitate the transmission of light

To act as a chaperone and protect target proteins from stress (correct)

To regulate the refractive index of the lens

To provide structural support to the lens

What determines the specific patterns of twisting and folding of proteins in the lens?

The sequence of nucleotides in the DNA

The 3D structure of the protein

The molecular weight of the protein

The sequence of amino acids in the protein (correct)

Which technique is most commonly used to determine the 3D structure of crystallin proteins?

X-ray crystallography Signup and view all the answers

What is a common characteristic shared by alpha, beta, and gamma crystallin proteins?

They are all globular proteins with different isoforms Signup and view all the answers

What is the significance of the shared characteristics among alpha, beta, and gamma crystallin proteins?

They are crucial for our understanding of the normal and abnormal lens Signup and view all the answers

What is the primary reason for the transparent nature of the lens?

The structural regularity of crystallins at the atomic and molecular level Signup and view all the answers

What is the characteristic of the aggregate formed by gamma crystallin?

Monomer with two self-associating domains Signup and view all the answers

What is the effect of disturbed packing of crystallins on light transmission?

It reduces light transmission Signup and view all the answers

What is the characteristic of the secondary structure of alpha crystallin?

Mostly alpha helices Signup and view all the answers

What is the reason for the high density of crystallins in lens cells?

The compact globular structure of crystallins Signup and view all the answers

What is the effect of the presence of enough crystallins in lens cells?

They are packed together at high density Signup and view all the answers

What is the role of α-crystallin in maintaining lens transparency?

It prevents protein aggregation by functioning as a molecular chaperone Signup and view all the answers

What is the characteristic of the dynamic quaternary structure of α-crystallin?

It is highly flexible and undergoes continuous exchange of subunits Signup and view all the answers

What is the advantage of using contrast variation in Small Angle Neutron Scattering (SANS)?

It enables the investigation of the location of target protein binding with high precision Signup and view all the answers

What is the characteristic of α-crystallin aggregates?

They are polydisperse and have different sizes Signup and view all the answers

What is the function of α-crystallin in response to denatured proteins?

It binds to the denatured proteins and prevents their aggregation Signup and view all the answers

What is the molecular weight of α-crystallin?

800 kDa Signup and view all the answers