Proteins

Proteins

large molecules comprised of 100s -1000s of Amino Acids (aa) held together by peptide bonds

Protein function

Enzymes (-ase), structural protein, transport,

Protein subunit

Amino Acids

Amino Acid Makeup

amino + α carbon with attached "R" + carboxylic acid

Amino Acid Structure

Classes of amino acids

• nonpolar

• polar

• negatively charged

• positively charged

Nonpolar amino acid group

hydrophobic; mostly hydrophobic force

Polar amino acid group

hydrophillic

Negatively Charged amino acid group

acidic

Positively charged amino acid group

basic

Peptide bonds

hold amino acids

Amino acid synthesis

N-Terminus to C-Terminus

N-Terminus

Amino H3N

C-Terminus

Carboxy COO

Dehydration Rxn

creates H20

Secondary Protein Structure

formation of α-helices and beta pleated sheets due to H-bonds

Tertiary Protein Structure

additional 3D globular folding due to R-group interactions

hydrophobic interactions tend to cluster interiorly

Quaternary Protein Structure

interaction between more than one polypeptide subunits

Denaturation

disruption of protein folding/shape