Ch. 4

Yes except for glycine

Cysteine - Stabilizes 3D structure of proteins

• Kinases are add a phosphate group to a protein. • ATP is the phosphate donor. • Commonly occur with Ser and Thr • Phosphatases remove the phosphate group TL;DR - add or remove a phosphate group

• Nonpolar • Proline: α helix breaker, imino acid • Methionine: first amino acid at N terminus of protein (AUG codon) • Polar • On surface of proteins in aquatic cell environment • Ser/thr/tyr • Can phosphorylate • Regulation of a protein’s activity • Basic • Parts of histones • Electrostatic interaction with DNA • Hydrophobic (have more C than H) • Can be part of membranes • Assist with transport • Acidic • Can interact with salts or metal ions • Aromatic (usually also hydrophobic and in membranes) • Strong absorbance at 280 nm

• Proteins • Source of energy • Regulation • Precursor to other biomolecules

An electrically neutral but dipolar molecule that contains both positive and negative charges

pH at which amino acid is neutral (no net charge) - Average the 2 pKa values that yield a neutral charge half the time

• Formed by condensation between the amine and carboxylic acid groups • Water is a product • Catalyzed by RNA component of ribosomes • Hydrolysis breaks peptide bonds • Catalyzed by proteases

Amino acid sequence

H bonds among backbone atoms

All 4 types of interactions between R groups

All 4 types of interactions between R groups to join more than one peptide

Proline