Protein Structure, Ligand Binding And Conformational Change- Amino Acid Sequence Determines Protein Structure Flashcards
What are proteins?
Polymers of amino acid monomers
What are amino acids linked by?
Peptide bonds to form polypeptides
How do amino acids differ in structure?
The R group present
What do R groups vary in?
-size
-shape
-charge
-hydrogen bonding capacity
-chemical reactivity
What are the different types of R group?
-basic (positively charged)
-acidic (negatively charged)
-polar
-hydrophobic
What happens as a result from diversity of R groups?
There is a wide range of different functions
What is the primary structure?
The sequence in which the amino acids are synthesised into the polypeptide
What is the secondary structure?
Hydrogen bonding along the backbone of the protein strand
What are the different types of secondary structures?
-Alpha helices
-Parallel or anti-parallel beta-pleated sheets
-turns
What is the tertiary structure?
The folded polypeptide
What is the conformation of the tertiary structure stabilised by?
Interactions between R groups
What are the different types of interactions between R groups?
-hydrophobic interactions
-ionic bonds
-ldf
-hydrogen bonds
-disulphide bridges (covalent bonds between R groups containing sulphur)
What is a quaternary structure?
They exists in proteins with two or more connected polypeptide subunits.
What does the quaternary structure describe?
The spatial arrangement of the subunits
What is a prosthetic group?
A non-protein unit tightly bound to a protein and necessary for it’s function
What is the ability of haemoglobin to bind oxygen dependent upon?
The non-protein haem group
What can interactions of the R groups be influenced by?
Temperature and pH
How is interactions of the R group influenced by temperature?
Increasing the temperature disrupts the interactions that hold the protein in shape, the protein then begins to unfold, eventually becoming denatured.
How is interactions of the R group influenced by pH?
The charges on acidic and basic R groups are effectived by pH. As pH increases or decreases from the optimum the normal ionic interactions between charged groups are lost which gradually changes the conformation of the protein until it becomes denatured
