Mrs. Einstein Research in Molecular Biology

Importance of proteins for cell function: Proteins are the end product of the central dogma YOU are your proteins Genome is the same in all cells, however cell types/functions vary widely Due to qualitative and quantities expression of proteins Proteins (P.C.F.NA.)

20 different types of amino acids The type of aa and it’s sequence will give the protein it’s unique 3D structure (function) Proteins are polymers of amino acids

Amino Acids are covalently linked through peptide bonds. A string of covalently bonded amino acids is called polypeptide chain.

final 3-D shape is determined by exact AA sequence for a typical protein of 300 AA, more than different proteins are possible! weak forces primarily determine the final 3-D topology of protein The 3-D Shape of a Protein Molecule is Determined by Its Amino Acid Sequence

Primary linear sequence of amino acids; amino and carboxy terminis Polypeptide chain Secondary initial folding of polypeptide backbone Tertiary final 3-D shape of protein Quarternary interaction of protein subunits Levels of Structural Organization in Protein

Secondary Level alpha (α) helix beta (β) pleated sheet random coil Common Folding Patterns Recur in Different Protein Chains

Disulfide bonds are strong covalent bonds between two cysteine residues Hydrogen bonds and hydrophobic forces between side chains also aid in protein folding Tertiary Structure

EX. Alpha helices typically will be found spanning the membrane of integral proteins (hydrophobic) EX. Amino acids found in the center of the protein tend to also be more hydrophobic and more hydrophilic aa residues are found on the surface Certain secondary structures are found in the same place in different proteins

Catalysis Structural Switching Binding 4 Major Classifications of Proteins

Viewing Protein Models WireSpace FillingRibbon

Identify the different parts of the amino acid. Board Question:

Draw the dipeptide created by the following two amino acids. Circle the side chains. Serine (S)Alanine (A) Board Question:

Protein Folding Activity