Unit 1 - Topic 2 - Proteins - Section C - Protein structure, ligand binding and conformational change - Part I - Amino acid sequence determines protein structure Flashcards
What are proteins
Polymers of amino acid monomers
How are amino acids linked
By peptide bonds to form polypeptides
Amino acids have the same basic structure differing only by what
The R group present
How do R groups of amino acids vary
In size, shape, charge, hydrogen bonding capacity and chemical reactivity.
Amino acids are classified according to their R groups which are
Basic (positively charged); acidic (negatively charged); polar; hydrophobic
The wide range of functions carried out by
proteins results from what
The diversity of R groups
What is the primary structure of a protein
The primary structure is the sequence in which the amino acids are synthesised into the polypeptide
What results in secondary structure and what are examples of secondary structures
Hydrogen bonding along the backbone of the protein strand results in regions of secondary structure — alpha helices, parallel or antiparallel beta-pleated sheets, or turns
What is tertiary structure
The polypeptide folds into a tertiary structure
Conformation is stabilised by interactions between R groups such as
Hydrophobic interactions; ionic bonds; London dispersion forces; hydrogen bonds; disulfide bridges
What are disulfide bridges
Covalent bonds between R groups containing sulfur.
Where does quaternary structure exist
In proteins with two or more connected polypeptide subunits
What is quaternary structure
Quaternary structure describes 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
The ability of haemoglobin to bind oxygen is
dependent upon what
The non-protein haem group
