Protein Structure Pt 2 Flashcards
What is primary structure of AA?
Basically the organisation and types of the amino acids within a peptide
What are the two main structures of proteins in secondary structures?
And what bond controls it?
Alpha helix and beta pleated sheets
Hydrogen bonds control the outcome of the secondary structure
What parts of the AA involved in secondary structure?
The hydrogen bonds between the N-H and C=O groups in polypeptide backbone
How prominent are h bonds in Alpha helices?
H bond between every 4th amino acid
How can alpha helix formation be disrupted?
Disrupted by AAs with large R groups as they distort the coil stopping h bonds
Best example is Aromatic proline
How many alpha helixes wrap around each other for stability,
2-3 Alpha helices wrap around each other with non polar side chains facing inwards (minimise contact with the aqueous cytosol)
Two types of beta pleated sheets?
Parallel beta sheet
Anti parallel beta sheet
Where can they be prominently found beta sheets?
Often found at core of proteins
What are usually prominent in beta turns?
Glycine and proline allow compact structures of secondary structure
What are the two categories of tertiary structure proteins?
1.Fibrous proteins like collagen,keratin(usually structural)
2.Globular proteins like enzymes (usually functional)
Briefly describe fibrous proteins structures
Very repetitive water insoluble and stable
Strand like
Two types of keratin and where they are found?
Alpha helical keratin found in human skin
Beta sheet keratins found in reptiles much stronger
What kind of proteins can globular proteins be made up of?
Can be made up of alpha and beta sheet proteins, a mix
Eg myoglobin is water soluble and mainly alpha helical
What bonds make up tertiary structure?
Disulphide bridges
Hydrogen bonds
VDW
Ionic bonds
Hydrophobic interactions
What is each polypeptide called within a quaternary structure?
Subunits (quaternary structure held by the same non covalent forces of tertiary structure?
