FOM 1.5.2

Question 1

Describe the general features of immunoglobulin structure

Answer 1

• Mostly beta sheets • Heavy and light chain attached with disulfide bonds: “protomer” considered a “monomer” • Tertiary structure can vary, monomeric, dimerice, pentameric • Two identical and INDEPENDENT ligand binding sites, specific to a particular antigen

Question 2

Compare and contrast the polypeptide sequence translated from insulin mRNA with the processed polypeptide

Answer 2

The insulin peptide is translated from a SINGLE mRNA but after it is processed, a portion is cleaved resulting into two pieces that bound together by two disulfide bonds. C-peptide portion is cleaved

Question 3

Describe higher order insulin structures and their corresponding functional effects.

Answer 3

Monomeric (acts quickly but effects are short-lived) –> dimeric (intermediate) –> hexameric (zinc required in the middle, acts slowly but effects are long-lived)

Question 4

Describe the structural consequences of covalently attaching PEG to the surface of a protein

Answer 4

PEG stabilizes protein structure (synthetic osmolyte) and prevents degradation

Question 5

C-peptide

Answer 5

portion of insulin peptide that gets cleaved leaving A and B peptide

Question 6

recombinant protein

Answer 6

protein not made in the native cell, ie human protein made in E. coli

Question 7

Describe the general features of ligand binding sites in multi-drug resistance (MDR)

Answer 7

MDR proteins are up regulated in cancer cells. It is thought that drugs that are hydrophobic (pink) and can easily pass through the membrane, if the P-glycoprotein is there, the drug goes to the P-glycoprotein binding site, causes a conformational change, and spits the drug back out meaning the drug can’t even get into the cytosol.

Question 8

Answer

Answer 8

D - reducing the disulfide bonds is going to break them. The two heavy chains are going to produce one band and the two light chains are going to produce another. This means that there is going to be 2 bands when the IG is reduced and 1 band when it is oxidized

Question 9

Answer 9

A - The recognition site are going to be what give the antibody its specificity

Question 10

What are the 3 requirement to make a functional insulin protein?

Answer 10

3 disulfide bonds to form

cleave the leader seq

Cleave the C-peptide

Question 11

Answer 11

B - these two amino acids are aromatic

Question 12

Answer this question then explain it. Also explain the different types of insulin.

Answer 12

A - Pt is zinc deficient so the body will want to pull off any extra zinc that it can obtain. This would cause the hexamer to behave more like the short acting.

There are three types. Monomeric - quick acting short lived

Dimeric- intermediate length

Hexameric - long acting requires zinc

Question 13

What is prion disease?

Answer 13

Pathological amyloid disease that results in the formation of amyloids in the body.

Question 14

Answer this

Answer 14

A - protein degradation but really to all

Question 15

Answer this

Answer 15

D - disposal, since prions are so stable and do not break a part, they must be disposed of