Flashcards in Amino Acids, Peptides, and Protein I Deck (45):
1
Hydrophobic and non-polar amino acids
Valine
Isoleucine
Leucine
Methionine
Phenylalanine
Tryptophan
Cystine
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2
hydrophilic and polar amino acids
argenine
lysine
aspartate
glutamate
asparagine
glutamine
3
acidic amino acids
aspartate
glutamate
4
basic amino acids
lysine
arginine
histidine
5
what may interactions between positive and negative R groups form?
salt bridge important for stabilization in proteins
6
what is a disulfide bond?
covalent linkage between two sulfer atoms specifically between cystine residues (thiol groups)
7
which amino acid has a sulfur bond but cannot participate in a disulfide bond?
methionine
8
where are disulfide bonds usually found within a folded protein?
on the inside because they are hydrophobic
9
what are the 6 major post-translational modifications that we need to know?
1. hydroxylation of proline
2. carboxylation of glutamate
3. modification by acetylation or methylation
4. glycosylation
5. reversible phosphorylation/dephosphorylation
6. ubiquination
10
what adds a hydroxyl group to proline residue?
prolyl hydroxylase
11
what is the predominate secondary structure in collagen and how is it formed?
proline helix
formed by multiple prolines and hydroxyprolines in a row
12
what is the cofactor of prolyl hydroxylase?
vitamin C
13
what disease results as a lack of vitamin C and which structure is affected?
scurvy, loss of integrity in connective tissues becase lack of proline hydroxylation
14
which enzyme adds a carboxyl group to the side chain of glutamate?
Gamma-glutamyl carboxylase
15
what is the co-factor of carboxylation of glutamate?
vitamin K
16
where is carboxylation of glutamate mostly found?
within clotting factors
17
what will a lack of vitamin K cause in regards to carboxylation of glutamate?
hemorrhage
18
how does waafarin work?
blood thinner that prevents clotting by inhibiting activity of gamma-glutamyl carboxylase
19
where does acetylation by HATs usually occur?
lysine residues of free tails of histones
20
where does methylation usually occur and by which enzyme?
lysine and arginine residues on histones by methyltransferases
21
what type of inhibitor is Vorinostat?
HDAC inhibitor
22
what is the mechanism of Vorinostat?
prevents removal of acetyl groups from histones. Tumors usually use deacetylation to repress tumor suppresor genes.
23
what is glycosylation?
attaching glycans (sugars) to proteins
24
what are the 4 types of glycans?
1. N-linked glycans
2. O-linked glycans
3. phospho-glycans
4. C-linked glycans
25
what amino acids to N-linked glycans attach to?
asparagine and arginine side chains
26
what amino acids to O-linked glycans attach to?
serine, threonine, tyrosine, hydroxylysine, hydroxyproline side chains
27
where do phospho-glycans attach?
phosphate of phospho-serine
28
where do C linked glycans attach?
carbon on tryptophan side chain
29
True of False
Glycosylation makes protein more polar
true
30
what is the purpose of glycosylation?
- proper protein folding
- increased stability of secreted glycoproteins
- cell to cell adhesion
- role in recognition
31
what genetic disease does disruption in N-glycosylation lead to?
Congenital disorder of glycosylation (CDG)
32
what is the presentation of congenital disorder of glycosylation (CDG)?
developmental delay and hypertonia
33
what mutation causes congenital disorder of glycosylation (CDG)?
PMM2 gene, autosomal recessive
34
which amino acids does phosphorylation usually occur?
serine, threonine, tyrosine
phosphate group added to OH
35
what does phosphorylation do?
activates or deactivates proteins and does reverse with dephosphorylation
36
what is the target of Gleevac?
bcr-abl tyrosine kinase
37
what disease is Gleevac used to treat?
Chronic myelogenous leukemia (CML)
38
what is the mechanism of action of Gleevac?
kinase inhibitor: prevents bcr-abl tyrosine kinase from phosphoyrlating tyrosine by competitively binding to active site
39
what is the most common type of modification of amino acids in cells?
ubiquination
40
what is the function of ubiquination?
targets protein for destruction from the proteosome
41
what is the process of ubiquination?
adds ubiquitin to lysine residues, addition of one recruits several more
42
what disease does bortezomib treat?
multiple myeloma
43
what kind of drug is bortezomib classified as?
proteasome inhibitor
44
what is the mechanism of bortezomib?
boron atom in bortezomib binds to catalytic site of 26S proteasome with high affinity and specificity
45