Protein Structure PDF

Protein Structure  Amino Acids - Protein building blocks An amino acid is a compound having both a carboxyl group(-COOH) and an amino group(-NH2). H All amino acids from protein have the -NH2 attached at H 2N C COOH the C ...

Protein Structure  Amino Acids - Protein building blocks An amino acid is a compound having both a carboxyl group(-COOH) and an amino group(-NH2). H All amino acids from protein have the -NH2 attached at H 2N C COOH the C  to the –COOH R (as well as the H- & R-).  Protein Structure Primary Assembly STRUCTURE PRO CESS Secondary Folding Tertiary Packing Quaternary Interaction  Secondary structure secondary structure, refers to local folded structures that form within a polypeptide due to interactions between atoms. The most common types of secondary structures are the α helix and the β pleated sheet. Both structures are held in shape by hydrogen bonds, which form between the carbonyl O of one amino acid and the amino H of another.  Proteins by Structure Fibrous Collagens Elastins Keratins Myosins bones lungs hair/feathers muscles tendons ligaments horn/nails cartilage  Proteins by Structure Globular Albumins Globulins egg whites antibodies(-globulin) enzymes  Proteins by Function Enzymes - the biological catalysts Contractile - muscle Hormones - insulin, growth hormone Neurotransmitters - endorphins Storage - store nutrients, eg. seeds, casein in milk Transport - hemoglobin Structural - collagen, keratins Protective - antibodies Toxins - snake venom, botulinum Denaturation is a specific property of proteins. It involves the change of the natural state of proteins. It is due to the rupture of chemical bonds that stabilize the secondary, tertiary and quaternary structure of the protein. It may be reversible or irreversible. Factors that produce denaturation: 1- Physical agents: As heat, ultraviolet irradiation, X-ray etc.... 2 - Chemical agents: As acids, alkalis, alcohols, urea etc.... Effects of denaturation on proteins: 1 - Loss of the secondary, tertiary and quaternary structure of proteins. 2 - Decreased solubility due to exposure of nonpolar hydrophobic groups. 4 - Increased digestibility by proteolytic enzymes due to exposure of peptide bonds. 5 - Loss of biologic activity e.g. inactivation of enzymes.