Protein levels of structure Flashcards
what are the 4 different heirachal structures for proteins
primary, secondary, tertiary and quaternary
primary structure
the linear seuqnece/order of amino acid in a polypeptide chain(s), they are often written as 3 letter acid codes with hyphens representing the peptide bonds
what does primary structure determine
as the order of aamino acids is unique to each protein it determines its function becuase it can then fold to form additinal structures
what is secondary structure
decribes the 3 dimensional form of local segments of a polypeptide chain, it is the result of the interactions between nearby amino acids
two examples of secondary structure
alpha helix and beta pleated sheets
examples of interactions between amino acids that cause secondary structure
negative r groups and positive r groups attract and polar r groups attract, pulling them closer to each other
what does polar mean, how is it shooown
when two elements are held by a covalent bond bond and the electrons arent shared evenly, e.g element is on a weird angle attached to another
what is an alpha helix
the right hand spiralling of the polypeptide, with the side chain pointing outwards, spiralling is caused by the repulsion between equally charged side chains
structure of alpha helix
is is held in a tight coil by the hydrogen bonds that form between the hydrogen from one amino acid and oxygen from four amino acids earlier
what does the alpha helix allow
the protein to stretch and then recoil and give a protein strength (e.g. keratin)
what is the strcture of the beta pleated sheets
when two or more lengths of a polypeptide run paralell/antiparallel and are held together by the hydrogen bonds between non-adjacent regions of the polypeptide
what do beta pleated sheets cause
for the protein to become more stretched and rigid the sheets make up fibroin (silk)
what is tertiary structure
the overall three dimensional shape of the protein, the shpe of the outer surface of the protein that is presented to other molecules
why does tertiary structure matter
the outer shape of a protein determines its function; biomacromolecules interact with each other mostly due to complementary shaoes and charrges
what rpoetins have quaternary structure
those with more than one polypeptide chain, results in globular or fibrous protein
