Flashcards in Amino Acids, Peptides, and Protein I Deck (45):
Hydrophobic and non-polar amino acids
(LIMP- TV Channel)
hydrophilic and polar amino acids
acidic amino acids
basic amino acids
what may interactions between positive and negative R groups form?
salt bridge important for stabilization in proteins
what is a disulfide bond?
covalent linkage between two sulfer atoms specifically between cystine residues (thiol groups)
which amino acid has a sulfur bond but cannot participate in a disulfide bond?
where are disulfide bonds usually found within a folded protein?
on the inside because they are hydrophobic
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
5. reversible phosphorylation/dephosphorylation
what adds a hydroxyl group to proline residue?
what is the predominate secondary structure in collagen and how is it formed?
formed by multiple prolines and hydroxyprolines in a row
what is the cofactor of prolyl hydroxylase?
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
which enzyme adds a carboxyl group to the side chain of glutamate?
what is the co-factor of carboxylation of glutamate?
where is carboxylation of glutamate mostly found?
within clotting factors
what will a lack of vitamin K cause in regards to carboxylation of glutamate?
how does waafarin work?
blood thinner that prevents clotting by inhibiting activity of gamma-glutamyl carboxylase
where does acetylation by HATs usually occur?
lysine residues of free tails of histones
where does methylation usually occur and by which enzyme?
lysine and arginine residues on histones by methyltransferases
what type of inhibitor is Vorinostat?
what is the mechanism of Vorinostat?
prevents removal of acetyl groups from histones. Tumors usually use deacetylation to repress tumor suppresor genes.
what is glycosylation?
attaching glycans (sugars) to proteins
what are the 4 types of glycans?
1. N-linked glycans
2. O-linked glycans
4. C-linked glycans
what amino acids to N-linked glycans attach to?
asparagine and arginine side chains
what amino acids to O-linked glycans attach to?
serine, threonine, tyrosine, hydroxylysine, hydroxyproline side chains
where do phospho-glycans attach?
phosphate of phospho-serine
where do C linked glycans attach?
carbon on tryptophan side chain
True of False
Glycosylation makes protein more polar
what is the purpose of glycosylation?
- proper protein folding
- increased stability of secreted glycoproteins
- cell to cell adhesion
- role in recognition
what genetic disease does disruption in N-glycosylation lead to?
Congenital disorder of glycosylation (CDG)
what is the presentation of congenital disorder of glycosylation (CDG)?
developmental delay and hypertonia
what mutation causes congenital disorder of glycosylation (CDG)?
PMM2 gene, autosomal recessive
which amino acids does phosphorylation usually occur?
serine, threonine, tyrosine
phosphate group added to OH
what does phosphorylation do?
activates or deactivates proteins and does reverse with dephosphorylation
what is the target of Gleevac?
bcr-abl tyrosine kinase
what disease is Gleevac used to treat?
Chronic myelogenous leukemia (CML)
what is the mechanism of action of Gleevac?
kinase inhibitor: prevents bcr-abl tyrosine kinase from phosphoyrlating tyrosine by competitively binding to active site
what is the most common type of modification of amino acids in cells?
what is the function of ubiquination?
targets protein for destruction from the proteosome
what is the process of ubiquination?
adds ubiquitin to lysine residues, addition of one recruits several more
what disease does bortezomib treat?
what kind of drug is bortezomib classified as?
what is the mechanism of bortezomib?
boron atom in bortezomib binds to catalytic site of 26S proteasome with high affinity and specificity