PROTEINSPROTEINS

by Radek Marták & Jiří Malinaby Radek Marták & Jiří Malina

Main characteristicsMain characteristics

Word Word proteinprotein = form Greek = form Greek ProtasProtas (Meaning of (Meaning of primary importanceprimary importance))

Protein is a complex, high-molecular Protein is a complex, high-molecular weight organic compound, that consists of weight organic compound, that consists of amino acids joined by peptide bonds.amino acids joined by peptide bonds.

Proteins were discovered by Jöns Jakob Proteins were discovered by Jöns Jakob Berzelius in 1838.Berzelius in 1838.

StructureStructure

Proteins are biopolymers build from Proteins are biopolymers build from 20 20 basic L-apha amino acidsbasic L-apha amino acids..

Structure of amino acids is responsible for Structure of amino acids is responsible for determining the final three-dimensional determining the final three-dimensional configuration of each protein.configuration of each protein.

We define primary, secondary, tertiary and We define primary, secondary, tertiary and quarternary structure.quarternary structure.

Overview of amino acidsOverview of amino acids

Primary structurePrimary structureIs given by sequence of amino acids.Is given by sequence of amino acids.

20 amino acids gives us about 20 amino acids gives us about (common protein = about 100 amino acids): 20100 = 1,27.10130 polypeptides

Secondary structureSecondary structure

Highly patterned sub-structures — Highly patterned sub-structures — alpha alpha helixhelix and and beta sheetbeta sheet — or segments of — or segments of chain that assume no stable shape and chain that assume no stable shape and are formed by hydrogen bonding.are formed by hydrogen bonding.

Secondary structures are locally defined, Secondary structures are locally defined, meaning that there can be many different meaning that there can be many different secondary motifs present in one single secondary motifs present in one single protein molecule. protein molecule.

Secondary structureSecondary structure

Tertiary structureTertiary structure

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

Tertiary structureTertiary structure

Quarternary structureQuarternary structure

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

Quarternary structureQuarternary structure

FunctionFunction

Structural proteinsStructural proteins

Transport and storage proteinsTransport and storage proteins

Immune response proteinsImmune response proteins

Signaling and regulatory proteins Signaling and regulatory proteins

Proteins involved in cell movementProteins involved in cell movement

Proteins involved in platellet aggregationProteins involved in platellet aggregation

Structural proteinsStructural 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

Transport and storage proteinsTransport 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)

Immune response proteinsImmune response proteins

Antibody molecules 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

Benefits in the dietBenefits in the diet

Protein is important to the human diet, supplying Protein is important to the human diet, supplying the body's needs for nitrogen and amino acids, the body's needs for nitrogen and amino acids, the building blocks of proteins.the building blocks of proteins.

Mammals cannot synthesize all 20 amino acids, Mammals cannot synthesize all 20 amino acids, so protein from the diet is necessary for life and so protein from the diet is necessary for life and the amino acids that cannot be synthesized by the amino acids that cannot be synthesized by the body are known as essential amino acids.the body are known as essential amino acids.

The exact amount of dietary protein needed for The exact amount of dietary protein needed for life may vary widely depending on age, sex, life may vary widely depending on age, sex, level of physical activity, and medical condition.level of physical activity, and medical condition.

Protein deficiencyProtein deficiency

Protein deficiency can lead to symptoms Protein deficiency can lead to symptoms such as fatigue, insulin resistance, hair such as fatigue, insulin resistance, hair loss, loss of hair pigment, loss of muscle loss, loss of hair pigment, loss of muscle mass, low body temperature, hormonal mass, low body temperature, hormonal irregularities, as well as loss of skin irregularities, as well as loss of skin elasticity.elasticity.

Severe protein deficiency, encountered Severe protein deficiency, encountered only in times of famine, is fatal, due to the only in times of famine, is fatal, due to the lack of material for the body to facilitate as lack of material for the body to facilitate as energy.energy.

Potential risks Potential risks Overreaction within the immune system Overreaction within the immune system

Liver dysfunction due to increased toxic Liver dysfunction due to increased toxic residues residues

Loss of bone density (calcium and Loss of bone density (calcium and glutamine is being leached from bone and glutamine is being leached from bone and muscle tissue to balance increased acid muscle tissue to balance increased acid intake from diet (blood pH is maintained at intake from diet (blood pH is maintained at around 7.4)around 7.4)

VocabularyVocabularyTendone – šlachaTendone – šlachaHorn – roh (zvířecí)Horn – roh (zvířecí)Nail – nehetNail – nehetVaccine – vakcínaVaccine – vakcínaAntibody – protilátkaAntibody – protilátkaLegumes – luskovinyLegumes – luskovinyVary – měnit seVary – měnit seMedical – zdravotníMedical – zdravotníMammals - savci Mammals - savci Lack – nedostatekLack – nedostatekFamine – hladomorFamine – hladomorFacilitate – usnadněnýFacilitate – usnadněnýFatique – únava, vyčerpanostFatique – únava, vyčerpanostLeached – „vyluhovaný“, (=vyčerpaný z kostí)Leached – „vyluhovaný“, (=vyčerpaný z kostí)

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