Protein Structure and Function - Lecture 4 Flashcards
What is a Primary Structure of Proteins?
A Sequence of amino acid residues
What is a Secondary Structure of Protein?
Localised conformation shape of the polypeptide backbone
What is the tertiary structure of protein?
The three dimensional structure of the entire polypeptide, including all its side
chains.
What is the Quaternary Structure of Proteins?
Spatial arrange of polypeptides chains in a protein with multiple chains.
What type of structures are amino acids?
Planar Structures
What bond helps form the secondary structure of proteins?
Hydrogen Bonds
Polypeptide Backbone
What are the examples of secondary structure?
Alpha Helix
Beta Sheet
How would you describe the type of twists in an alpha helix?
Right Handed Twists
What is Proline’s effect on an Alpha Helix?
Proline residues break alpha helices - Proline puts in a left handed 90 turn
What are the two types of Beta Sheets?
Parallel
Aniparallel
Describe the structure of a Beta Sheet?
Polypeptide backbone almost completely extended.
Beta Pleated sheets have a zigzag structure
What is Collagen?
Component of Bone or Connective Tissue
What is the repeating sequence of Collagen?
Amino Acid
Proline
Glycine
Describe the Strucutre of Collagen?
Beta Pleated sheets have a zigzag structure
Can have flat sheets or pleated sheets
There are only inter-chain H bonds, no intra chain.
There are inter and intra-molecular covalent bonds.
What are the two groups of Tertiary Protein?
Fibrous Protein
Globular Protein
What are the features of a Fibrous Protein?
Insoluble in water and dilute salt solutions
Polypeptide chains organised approximately parallel along a single axis.
Mechanically strong
Structural roles.
What are the features of a Globular Protein?
Soluble in water and salt solutions
Spherical shapes.
Polar side chains are on the outside and interact with the aqueous environment
Non polar components are buried inside
Substantial Secondary Structures articulate
What are the forces that stabilies a tertiary protein?
Covalent disulphide bonds
Electrostatic interactions = salt bridges
Hydrophobic interactions
Complex formation with metal ions
What are the features of a Disulphide bond?
Readily reversible
Detects oxygen free radicals, can cause ion channels to open and to
close
What may occur to a protein if an amino acid is omitted?
Leads to significant functional changes
What helps the folding process of a protein?
A Chaperone protein
What causes Creutzfeldt -Jacob Disease?
Disease Prion Protein (PrPsc)
What is the normal form of Prion Protein?
Normal form of Prion protein termed PrPc
What is disruption of a protein called?
Denaturation
How many Oxygen can Haemoglobin carry?
4
Each Haem group can carry one
What is the redox centre of Haemoglobin?
Iron atom
