PROTEINS

1. PROTEINS by Radek Marták & Jiří Malina

2. Main characteristics • Word protein = form Greek Protas (Meaning of primary importance) • Protein is a complex, high-molecular weight organic compound, that consists of amino acids joined by peptide bonds. • Proteins were discovered by Jöns Jakob Berzelius in 1838.

3. Structure • Proteins are biopolymers build from 20 basic L-apha amino acids. • Structure of amino acids is responsible for determining the final three-dimensional configuration of each protein. • We define primary, secondary, tertiary and quarternary structure.

4. Overview of amino acids

5. Primary structure • Is given by sequence of amino acids. • 20 amino acids gives us about (common protein = about 100 amino acids): 20100 = 1,27.10130 polypeptides

6. Secondary structure • Highly patterned sub-structures — alpha helix and beta sheet — or segments of chain that assume no stable shape and are formed by hydrogen bonding. • Secondary structures are locally defined, meaning that there can be many different secondary motifs present in one single protein molecule.

7. Secondary structure

8. Tertiary structure • Unique three-dimensional conformation that globular proteins assume as a consequence of the non-covalent interactions between the side chains in their primary structure • primarily formed by hydrophobic interactions, but hydrogen bonds, ionic interactions, and disulfide bonds are usually involved too.

9. Tertiary structure

10. Quarternary structure • the shape or structure that results from the union of more than one protein molecule, usually called protein subunits in this context, which function as part of the larger assembly or protein complex.

11. Quarternary structure

12. Function • Structural proteins • Transport and storage proteins • Immune response proteins • Signaling and regulatory proteins • Proteins involved in cell movement • Proteins involved in platellet aggregation

13. Structural proteins • Structural proteins typically contain high proportions of regular secondary structures such as α-helix or β-pleated sheet • As a consequence of their rodlike or sheetlike shapes, these proteins exhibit fibrous character and have structural rather than dynamic roles • Examples of fibrous proteins include keratin (horn, nail), collagen (skin, bones, tendones), elastin and silk fibroin

14. Transport and storage proteins • Storage of amino acids and other important substances • Ovalbumin (egg) • Casein (milk) • Legumin (legumes) • Gliadin, zein (corn) • Ferritin (storage of Fe in ) • Transport proteins • Serum albumin – an universal transport protein • Hemoglobin (oxygen-binding protein - circulation) • Myoglobin (oxygen-binding protein - muscles) • Transferrin (transport of Fe)

15. Immune response proteins • Antibodymolecules are produced in response to invasion by foreing compounds that can be proteins, carbohydrate polymers, and nucleic acids • All antibodies have a similar structure • Immunization – vaccine consists of killed bacterial cells, inactivates viruses, killed parasites, a nonvirulent form of live bacterium, a denaturated bacterial toxin or recombinnt protein

16. Benefits in the diet • Protein is important to the human diet, supplying the body's needs for nitrogen and amino acids, the building blocks of proteins. • Mammals cannot synthesize all 20 amino acids, so protein from the diet is necessary for life and the amino acids that cannot be synthesized by the body are known as essential amino acids. • The exact amount of dietary protein needed for life may vary widely depending on age, sex, level of physical activity, and medical condition.

17. Protein deficiency • Protein deficiency can lead to symptoms such as fatigue, insulin resistance, hair loss, loss of hair pigment, loss of muscle mass, low body temperature, hormonal irregularities, as well as loss of skin elasticity. • Severe protein deficiency, encountered only in times of famine, is fatal, due to the lack of material for the body to facilitate as energy.

18. Potential risks • Overreaction within the immune system • Liver dysfunction due to increased toxic residues • Loss of bone density (calcium and glutamine is being leached from bone and muscle tissue to balance increased acid intake from diet (blood pH is maintained at around 7.4)

19. Vocabulary • Tendone – šlacha • Horn – roh (zvířecí) • Nail – nehet • Vaccine – vakcína • Antibody – protilátka • Legumes – luskoviny • Vary – měnit se • Medical – zdravotní • Mammals - savci • Lack – nedostatek • Famine – hladomor • Facilitate – usnadněný • Fatique – únava, vyčerpanost • Leached – „vyluhovaný“, (=vyčerpaný z kostí)

20. Thanx for your attention!! Bye. And last small easy picture of protein for you 