Protein Structure Flashcards
What is the backbone structure of all proteins?
N-C-C-N
What gives the function of a protein?
The different side chains attached
How many different R groups are there?
20
What stays the same and what changes throughout different proteins?
Backbone structure stays the same
Side chains change
What is the secondary structure of a protein?
Organisation of the side chains
What are the 3 possible secondary structures of a protein?
Alpha-helix
Beta-pleated sheet
Random coil
How is the secondary structure of a protein held together?
By weak hydrogen bonds
What happens to H bonds in a protein?
Continuously breaking and reforming without enzymatic activity
What is the tertiary structure of a protein?
Globular structure, in which the individual structural elements (a-helix, beta-pleated sheet, random coil) pack together
WITHIN a protein and BETWEEN subdomains of a protein
The entire structure of 1 protein
What is the quaternary structure of a protein?
Multimeric protein of many proteins interacting together
many tertiary structures
What must be considered when considering the activity of the protein and why?
Example
ALL of the structures of the protein (primary–> quaternary) as a feature in one structure may impact the activity of another
Example: A protein in the primary structure may be able to be phosphorylated, which could impact how proteins interact with each other in the multipmeric quaternary structure
What are the hydrophobic amino acids?
Alanine (Ala) isoleucine (Ile) Leucine (Leu) Methionine (Met) Phenylalanine (Phe) Valine (Val) Glycine (Gly) Proline (Pro)
What are hydrogen bonds?
Weak bonding between H and O or H and N
What are ionic bonds?
Electrostatic forces between positive and negative charges
What are Van der Walls?
Very weak, short range interactions between molecules
What are the 4 different representations of a secondary protein structure?
Describe them
1) Backbone
- Skeleton of the C-N backbone
2) Sticks
- Shows ALL the connections between all of the atoms
- Back-bone and side chains
3) Space-filling
- Shows protein in a globular manner and all the pockets for interaction with other molecules
4) Ribbon
- Describes the motif
- Flattened
Which representation of a protein is more true to life?
The space-filling representation
What is important for function in a protein?
Structure/shape
What is Src?
A multidomain tyrosine kinase
What is Src involved with?
Cancer
What are the 4 domains of Src?
- SH2
- SH3
- Small kinase domain
- Large kinase domain
How are the structure and functions of the domains in a multi-domain complex related to each other?
They normally have in dependant structures and functions
But all work together to achieve the task of the protein
How can domains in a protein show a common ancestor?
Same domains - through evolution they are conserved and paired with other domains to achieve different functions