protein structure #7 Flashcards
classifications of proteins
Simple: only a chain of amino acids forming a polypeptide.
Modified: or conjugated proteins. Proteins which contain other types of molecule as a prosthetic group
Explain the structure of amino acids found within proteins in the body
All amino acids in proteins are L-amino acids.
D- amino acids are neurotransmitters. Amino acids are alpha acids
protein molecules are a long branched/unbranched?
unbranched
How are amino acids arranged?
According to side chain properties into acid, basic, polar and non polar.
Explain the peptide bond.
The peptide bond is formed by dehydration forming an amide bond. The peptides are inbetween a single and double bond. It has some of the properties of a double bond. This makes it rigid.
What’s the beginning and end of the polypeptide chain
the N terminal is the beginning
What is the isoelectric point and how is it affected?
is the pH at which the net charge of a protein is 0. For a protein with many basic amino acids the pL is high
What is the primary structure?
Is only made by the order of amino acids and is stabilised by covalent peptide bonds. There are 20n different possibilities for polypeptides (where n is the number of amino acids in the polypeptide).
What is the secondary structure?
It is regular and ordered conformation which involve local interactions between the backbone groups, the side chains have less of an effect on the secondary structure. They are formed by hydrogen bonds which form between the groups in the backbone. These occur to hide hydrophobic portions and to expose hydrophilic residues. The secondary structures maximise the interaction between C and N
the protein backbone is
highly polar due to N-H, C-O
what are protein domains
stable units of protein structure that could fold autonomously
