Questão 1
Questão
Physical modifications are reversible
Questão 2
Questão
Give an example of protein oxidation
Questão 3
Questão
Where are proteins with oxidated modifications are nearly universally found where?
Questão 4
Questão
What is so useful about disulphide bonds?
Questão 5
Questão
Where do oxidation reactions occur?
Responda
-
The golgi
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The ER
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The ribosome
Questão 6
Questão
Disulphide bonds assist in recovery from denaturation
Questão 7
Questão
In Maristoylation, what is added?
Responda
-
Maristic acid
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Maristoylate
-
Maristoyl-3-phosphate
Questão 8
Questão
Describe the substrate added in Myristoylation
Questão 9
Questão
What is the point of Myristoylation?
Questão 10
Questão
What sequence is the Myristoylation substrated added to?
Responda
-
The N-terminus
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The C-terminus
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MGXXX(T/S)
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MPXXX(G/F)
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SDXXX(S/R)
Questão 11
Questão
The protein that performs Myristoylation is N-Myristoyl transferase
Questão 12
Questão
How is the Myristoylation substrate added?
Responda
-
First the phenylalinine is removed
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First the methionine is removed
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First the tyrosine is removed
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Then the substrate is added to the glycine
-
Then the substrate is added to the leucine
-
Then the substrate is added to the isoleucine
Questão 13
Questão
Prenylation is the addition of ketones
Questão 14
Questão
Name the two substrates most often added in prenylation
Responda
-
Farnesyl
-
Geranylgeranyl
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Derisyl
-
Nitrosyl
Questão 15
Questão
Where does prenylation occur?
Responda
-
In a CAAX box (where A should be Alanine, but anything small and hydrophobic will do)
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In a FAAX box (where A should be Isoleucine, but anything small and hydrophobic will do)
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In a CAAT box (where A should be Alanine, but anything small and hydrophobic will do)
Questão 16
Questão
In prenylation, the X of the sequence must be the terminal aa of the chain
Questão 17
Questão
Put the following in order
A- The COOH group is modified to a methyl group to make it uncharged
B- The substrate is added to the cystine
C- The last three aa are removed
Questão 18
Questão
Prenylation is done to proteins destined for the cytoplasm
Questão 19
Questão
Name the types of glycosylation
Responda
-
N-linked
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O-linked
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C-Mannosylation
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Phosphoserine Linked
Questão 20
Questão
Glycosylation is the addition of carbohydrate chains
Questão 21
Questão
What is the site of N-linked glycosylation?
Responda
-
The Asn in an NX(S/T)
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The Phe in an FX(S/T)
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The Gly in a GX(S/T)
Questão 22
Questão
What is the residue that is attached to the amino acid?
Responda
-
Mannose
-
Glucose
-
N-acetyl-galactosamine
-
N-acetyl glucosamine
Questão 23
Questão
What residues are on the tips of the branches?
Questão 24
Questão
If the branches end with mannose, what is the process called?
Questão 25
Questão
Why are 3 glucose added to the sugar complex in the golgi?
Responda
-
So they can be removed as markers for protein folding and transport
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So the Golgi knows they're bound for the membrane
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So the Golgi can degrade the protein as faulty
Questão 26
Questão
Why is it called High-Mannose Biantennary N-Glycosylation?
Responda
-
Because one of the three branches is removed, giving two 'antenna'
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Because another branch is formed off the first one, giving two 'antenna'
-
Because proteins with this type of glycosylation act as receptor proteins with two antenna
Questão 27
Questão
Once the Biantennary complex has been formed, what happens next?
Responda
-
Mannose is removed
-
Addition of N-acetyl neuraminic acids
-
Addition of glucose
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Removal of N-acetyl glucosamine
-
Addition of a fucose to the GlcNac bound to the amino acid
Questão 28
Questão
Why the complicated process of adding and removing sugars?
Responda
-
It adds a date stamp to the cell- over time the NeuAc's fall off, which signals the protein for degredation
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It adds a transport signal- depending on what is added or removed, proteins are directed to different areas by carrier proteins
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It's quality control- the contortions required to add and remove all the sugars mean that the protein has folded properly
Questão 29
Questão
The HIV virus can use glycosylation to hide from the immune system
Questão 30
Questão
Why is N-linked glycosylation potentially dangerous?
Responda
-
Because the immune system is programmed to ignore it, viral coat proteins can use it to hide the virus
-
Because NeuAc's can be toxic in high concentrations
-
Because the removal of mannose can cause the protein to misfold
Questão 31
Questão
HIV1-gp120 has many N-X-(T/S) sequences to be glycosylated
Questão 32
Questão
Where does HIV1-gp120 bind?
Responda
-
CD4 receptor
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CD8 receptor
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B-lymphocyte receptors
Questão 33
Questão
How does the HIV virus invade the lyphocyte?
Responda
-
It's only glycosylated on a very small binding site
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It's only not glycosylated on a very small binding site
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Which allows it to bind and invade