Protein Structure and Function

barnes@mail.clarion.edu             Send questions or comments to Dr. Barnes!
 
 
Protein Structure amino acids primary structure secondary structure tertiary structure quaternary structure
Protein Function Structure, SHAPE, and Function of Tools Structure, SHAPE, and Function of Proteins Arabinose Transporter Hexokinase

 
 


 
 

A.   Protein Structure  ---- full explanation

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OVERVIEW
  1. Proteins are polymers in which the subunits are amino acids. 
  2. The primary structure of proteins is the sequence of amino acids which is specific to each one. 
  3. The amino acid chain may "kink" and "coil" into secondary structures such as alpha helix; beta pleated sheet; random coil.
  4. The secondary structures pack and fold together which produces a SHAPE;  this is called  tertiary structure. 
  5. Quaternary structure occurs when 2 or more proteins bind together and work cooperatively.


 
 

B.  Protein Function ---- full explanation

OVERVIEW
  1. A characteristic SHAPE ultimately results from the hierarchical structure of proteins:  primary structure ---> secondary structure ---> tertiary structure ---> quaternary structure

    2.  
  2. This shape is critical because most proteins function by binding to molecules (a substrate or a ligand) or to another protein ....... this requires complementary fit ..............  the shape of the protein (which is determined by its structure)  must be correct in order to match the shape of the substrate or ligand!

    3.  
  3. For example:  the shape of the active site of an enzyme must be complementary to the shape of the substrate molecule.  This enables, the substrate to fit into the active site;  as a result the enzyme catalyzes a biochemical reaction.

    4.  
  4. If the biochemical reaction is catalyzed, then metabolism is normal and the phenotype is normal.

 
 


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