Proteins Prt 2 Flashcards
what does the amino acid sequence determine
Amino acid sequence determines protein structure
what are proteins
Proteins are polymers of amino acid monomers
what are amino acids linked by
Amino acids are linked by peptide bonds to form polypeptides
what structure do amino acids have
Amino acids have the same basic structure, differing only in the R group present
how are amino acids classified
Amino acids are classified according to their R groups: basic (positively charged); acidic (negatively charged); polar; hydrophobic
what does the wide range of functions carried out by proteins result from
The wide range of functions carried out by proteins results from the diversity of R groups
what is the primary structure
The primary structure is the sequence in which the amino acids are synthesised into the polypeptide
what does hydrogen bonding along the backbone of the protein strand result in
hydrogen bonding along the backbone of the protein strand results in regions of secondary structure — alpha helices, parallel or anti-parallel beta-pleated sheets, or turns
what bonds stabilize the interaction between r groups in a tertiary structure
The polypeptide folds into a tertiary structure
This conformation is stabilised by interactions between R groups: hydrophobic interactions; ionic bonds; London dispersion forces; hydrogen bonds; disulfide bridges
where does a Quaternary structure exist
Quaternary structure exists in proteins with two or more connected polypeptide subunits
what is a prosthetic group
A prosthetic group is a non-protein unit tightly bound to a protein and necessary for its function
what can interactions of the R groups be influenced by
Interactions of the R groups can be influenced by temperature and pH
what does ligand binding do
Ligand binding changes the conformation of a protein
what is a ligand?
A ligand is a substance that can bind to a protein
what are the R groups not involved in protein folding for
R groups not involved in protein folding can allow binding to ligands
what do binding sites have
Binding sites will have complementary shapes and chemistry to the ligand
what happens as a ligand binds to a protein-binding site
As a ligand binds to a protein-binding site the conformation of the protein changes. This change in conformation causes a functional change in the protein
what do Allosteric interactions occur between
Allosteric interactions occur between spatially distinct sites
what do many allosteric proteins consist of
Many allosteric proteins consist of multiple subunits (have quaternary structure)
what do allosteric proteins with multiple subunits show
Allosteric proteins with multiple subunits show co-operativity in binding, in which changes in binding at one subunit alter the affinity of the remaining subunits
what do allosteric enzymes contain
Allosteric enzymes contain a second type of site, called an allosteric site
what do modulators regulate
Modulators regulate the activity of the enzyme when they bind to the allosteric site
following the binding of a modulator what happens
Following binding of a modulator, the conformation of the enzyme changes and this alters the affinity of the active site for the substrate
what does the binding and release of oxygen in haemoglobin show
The binding and release of oxygen in haemoglobin shows co-operativity
