Protein Structure Flashcards
What are the 4 roles of proteins?
- Structures
- Communicators
- Transporters
- Catalysts
In all cases, a protein’s function is determined by…
Its structure
What determines the 3D shape of a protein?
Phosphodiester bonds, bond stacking, and hydrogen bonds (minimally)
When the pH is below the pKa, is the structure protonated or deprotonated?
Protonated (Keeps H+ out of solution to increase pH)
When the pH is above the pKa, is the structure protonated or deprotonated?
Deprotonated (releasing H+ to bring down pH)
When the pH is equal to the pKa, is the structure protonated or deprotonated?
50% of each as it is equally dissociated
pKa: -COOH
~2
pKa: -NH3+
~9.5
pKa: -SH
~9
Define
Zwitterion
A molecule that contains an equal number of
positively and negatively charged functional
groups
When is an amino acid zwitterion?
If the R group has a charge
Define
Chiral
A molecule that cannot be superimposed on its mirror image
Define
Stereoisomers
Molecules with the same bonds, but with different orientations
Hydrophobic amino acids
Always Take Part In Promoting Mother Language (Alanine, tryptophan, phenylalanine, isoleucine, proline, methionine, leucine)
What are the overarching characteristics about the hydrophobic amino acids?
- Lack reactive functional groups
- Have mainly hydrocarbon side chains
- R groups do not have a pKa value
is alanine aliphatic or aromatic?
Aliphatic
