Amino Acids Flashcards
(19 cards)
Which amino acid constrains the backbone the least and why?
Glycine because it has the smallest side group being a hydrogen.
Which amino acids constrains the backbone the most and why?
Proline because it has strong steric hindrance or chemical constraints than in any other residue having only one instead of two variable backbone angles and it lacks the normal NH backbone for hydrogen bonding.
Which amino acids are uncharged polar?
Y S T C N Q
Which amino acids are nonpolar?
C A P V L Ile M F W
Which amino acids are charged?
K R H D E
Which amino acids are aromatic?
F W Y
Which amino acids are beta-branched?
Ile V T
Which amino acids contain a hydroxyl side chain?
S T Y
Which amino acids contain a carboxyl side chain?
E D
Which amino acids contain an amino side chain?
K R
Where are phi torsion angles located?
Around N to Calpha (first residue does not have one)
Where are the psi torsion angles located?
Around Calpha to Carbon bond (last residue does not have one)
How many atoms and bonds are required for a torsion angle?
4 atoms and 3 bonds
How many chiral centers does glycine have?
None
Given a pKa and a pH, how do you solve for the base/acid ratio?
pH=pKa+log([A^-]/[HA])
Can the S-H group of cysteine form hydrogen bonds? Why or Why not?
Yes it can because it has a higher electro negativity than hydrogen.
If the S-H group of cysteine can form hydrogen bonds, would you expect them to be stronger or weaker than those found in water? Why?
Sulfur is less electronegative so it will be weaker than those found in water.
Give the names of amino acid residues in a protein whose side chains can form hydrogen bonds of electrostatic bonds with the side chain of an arginine residue.
H-bonds: Y, S, T, M, N, Q, C
Electrostatic bonds: D, E
What is unique about the peptide bond? Explain.
The peptide bond is rigid and planar. This is due to resonance occurring and allowing the C to N to have a partial double bond.
