1.2.3 protein structure, ligand binding, conformational change Flashcards
what determines protein structure
amino acid sequence
what are proteins
polymers of amino acid monomers
what are amino acids linked with to form polypeptides
peptide bonds
do amino acids have the same basic structure
yes
how do amino acid structures differ
the R group present
how do R groups of amino acids vary
- size
- shape
- charge
- hydrogen bonding capacity
- chemical reactivity
how are amino acids classified
according to their R groups
what are the different amino acid classifications
- basic (positively charged)
- acidic (negatively charged)
- polar
- hydrophobic
what does the diversity of the R groups of amino acids result in
the amino acids having a wide range of functions carried out by their proteins
what is the primary structure
the sequence in which the amino acids are synthesised into the polypeptide
what results in the secondary structure
hydrogen bonding along the backbone of the protein strand results in regions of secondary structure
what are examples of the secondary structures
- alpha helices
- parallel beta-pleated sheets
- anti-parallel beta-pleated sheets
- turns
what does the polypeptide structure fold into
tertiary structure
what stabilizes the tertiary structure (give examples)
interactions between R groups
- hydrophobic interactions
- ionic bonds
- london dispersion forces
- hydrogen bonds
- disulfide bridges
what are disulfide bridges
covalent bonds between R groups containing sulfur
when does a quaternary structure exist
in proteins with two or more connected polypeptide subunits
what is a quaternary structure
the spatial arrangement of the subunits
what is a prosthetic group
a non protein unit tightly bound to a protein and necessary for its function
what is the ability of haemoglobin to bind oxygen dependent on
the non protein haem group
what can influence the interactions of the R groups
- temperature
- pH
what happens to proteins when you increase the temperature
- the increased temperature disrupts the interactions that hold the protein in shape
- the protein begins to unfold, eventually becoming denatured