amino acids and proteins Flashcards
(46 cards)
basic structure of amino acids
nh3 group
central carbon
cooh group
hydrogen
all amino acids are
L- amino acids
what kind of organisms have d amino acids
bacteria
which orientation are most amino acids? R/s?
most are S with the exception of cystine
what is the R/S configuration of cysteine
R
aliphatic amino acids
G, A, V, L, I, P
is methionine polar or nonpolar
nonpolar
what is unique about proline?
it disrupts secondary protein stucture and causes proline kinks
which amino acids can be phosphorylated
serine, threonine, tyrosine on their -OH residues
what is unique about histidine?
pka of 6.0 so it acts as a buffer at physiological pH
amide amino acids
glutamine (Q) asparagine (N)
sulfur containing amino acids
cysteine and methionine
which amino acids are achiral
glycine only
peptide bond
hydrolysis reaction that takes the OH group from a COOH and the next H from an NH3 group
proteases
hydration reaction that breaks up primary structure/ breaks the peptide bonds
average protein size
50 kDa
how are proteins assembled in the ribosome
from the N to C terminus
terciary structure
interactions are typically non-covalent and charge driven.
- salt bridges
- disulfide bridges
2- mercatoethanol
a reducing agent that breaks up disulfide bonds
what kind of bond are disulfide bridges
COVALENT
- very strong compared to most tericiary interactions
where does hydrogen bonding occur in secondary structure of proteins
between the COOH anf NH3 residues of the protein backbone
what structure do proteases cleave
primary
what structure do denaturing agents cleave?
2, 3, 4
- not permenent
taq polymerase
a protein that is challenging to denature at high temp and is used in PCR technique
