Proteins: Building Blocks of Life PDF

Proteins: Building Blocks of Life Proteins are essential for all life forms, playing critical roles in various biological processes. In this presentation, we'll delve into the fascinating world of proteins, exploring their structure, function, classification, and importance in the body. by Stef...

Proteins: Building Blocks of Life Proteins are essential for all life forms, playing critical roles in various biological processes. In this presentation, we'll delve into the fascinating world of proteins, exploring their structure, function, classification, and importance in the body. by Steffy Largo Functions of Proteins Enzymes Antibodies Proteins act as catalysts, speeding Proteins form the basis of our up biochemical reactions within immune system, recognizing and cells. They are vital for neutralizing pathogens like metabolism, digestion, and many bacteria and viruses. other processes. Transport Structure Proteins transport molecules and Proteins provide structural support ions throughout the body. For and mechanical strength. They are example, hemoglobin carries essential for cell shape, muscle oxygen in red blood cells. function, and tissue integrity. Amino Acids: The Building Blocks General Structure Properties All amino acids share a common structure: a central carbon Amino acids exhibit amphoteric behavior, meaning they can act atom bonded to an amino group (-NH2), a carboxyl group (- as both acids and bases. The R-group determines the amino COOH), a hydrogen atom (-H), and a unique side chain (R- acid's unique properties, influencing its function and group). interactions with other molecules. Classification of Amino Acids Nonpolar Polar These amino acids have hydrophobic R-groups and These amino acids have hydrophilic R-groups, tend to cluster together within proteins, influencing forming hydrogen bonds with water and other polar their shape and interactions with water. Examples: molecules. They are often found on the surface of Glycine, Alanine, Valine, Leucine, Isoleucine, proteins, interacting with the aqueous environment. Phenylalanine, Tryptophan, Methionine, Proline. Examples: Serine, Threonine, Tyrosine, Asparagine, Glutamine. Acidic Basic These amino acids contain a negatively charged These amino acids have a positively charged amino carboxylate group in their R-group. They contribute group in their R-group. They influence protein charge to the overall charge of proteins and can participate and can form ionic bonds with acidic amino acids. in ionic interactions. Examples: Aspartic Acid, Examples: Lysine, Arginine, Histidine. Glutamic Acid. Essential Amino Acids 1 Isoleucine 2 Leucine 3 Lysine Essential for muscle growth and Essential for muscle growth and Essential for bone health, repair, as well as hormone repair, and helps regulate blood collagen production, and immune production. sugar levels. function. 4 Threonine 5 Tryptophan 6 Methionine Essential for collagen production, Essential for serotonin Essential for detoxification, immune function, and healthy production, which helps regulate collagen production, and hair and skin. mood and sleep. nail growth. 7 Histidine 8 Valine 9 Phenylalanine Essential for growth and repair, Essential for muscle growth and Essential for production of as well as immune function. repair, and helps regulate blood tyrosine, dopamine, and sugar levels. norepinephrine, which affect mood and cognitive function. Protein Structure Primary 1 Linear sequence of amino acids. Secondary 2 Local folding patterns, including alpha-helices and beta-sheets. Tertiary 3 Overall three-dimensional shape of a single polypeptide chain. Quaternary 4 Arrangement of multiple polypeptide chains (subunits) in a protein complex. Protein Denaturation Heat: Disrupts weak bonds, causing unfolding. 1 2 pH changes: Alters the ionization state of amino acids, disrupting interactions. Chemicals: Detergents, salts, or heavy metals 3 can disrupt bonds and alter protein conformation. 4 Mechanical agitation: Shaking or stirring can disrupt the delicate structure of proteins. Loss of function: Denatured proteins often lose 5 their biological activity. Significance of Protein Denaturation Cooking 1 Heat denatures proteins in food, making them easier to digest and altering their texture. Food Preservation 2 Denaturation can be used to preserve food by inactivating enzymes that cause spoilage. Medical Applications 3 Denaturation is used in sterilization techniques to eliminate pathogens and in some drug delivery methods. Industrial Processes 4 Denaturation is used in leather tanning, textile production, and other industrial processes involving proteins. Protein Synthesis Transcription Genetic information in DNA is copied into mRNA. Translation mRNA is decoded by ribosomes to assemble amino acids into a polypeptide chain. Folding The polypeptide chain folds into a specific three- dimensional structure, guided by interactions between amino acids. Summary and Key Takeaways 20 4 Amino Acids Levels of Structure Proteins are composed of 20 Proteins have four levels of different amino acids, each with structure: primary, secondary, unique properties. tertiary, and quaternary. 1 1 Essential Denaturation Nine amino acids are essential for Denaturation can alter protein human health and must be function and has various obtained from diet. applications in food science, medicine, and industry. The Structure of Proteins Proteins are essential molecules in all living organisms. They play a vital role in many cellular processes, including structure, catalysis, transport, and signaling. Understanding the structure of proteins is crucial for understanding their function. This presentation will explore the different levels of protein structure and how they contribute to the overall function of a protein. by Steffy Largo Peptide Bonds: Building Blocks of Proteins Proteins are made up of amino acid monomers joined together by peptide bonds. These bonds form between the carboxyl group of one amino acid and the amino group of another, releasing a molecule of water. Dipeptide Tripeptide Polypeptide A dipeptide is formed when two A tripeptide is formed when three A polypeptide is a chain of many amino acids are joined by a amino acids are joined by peptide amino acids joined by peptide peptide bond. bonds. bonds. Proteins are made up of one or more polypeptide chains. Primary Structure: The Amino Acid Sequence The primary structure of a protein refers to the specific sequence of amino acids in the polypeptide chain. It is like the "recipe" that determines the protein's overall shape and function. Sequence 1 Linear arrangement of amino acids linked by peptide bonds. Genetic Code 2 Determined by the DNA sequence. Function 3 Influences the protein's overall shape and function. Secondary Structure: Local Folding Patterns The secondary structure refers to the local, regularly repeating structures within a polypeptide chain. These structures arise from hydrogen bonding interactions between backbone atoms. 1 Alpha Helix 2 Beta Sheet A coiled structure A sheet-like structure stabilized by hydrogen formed by hydrogen bonds between bonds between backbone atoms. Alpha polypeptide strands. helices are often found Beta sheets are less in transmembrane flexible than alpha proteins and are flexible helices and are more and elastic. resistant to stretching. Tertiary Structure: 3D Folding The tertiary structure of a protein refers to its overall three-dimensional shape. This structure arises from interactions between the side chains of amino acids, leading to a compact and functional protein. Hydrophobic Interactions Hydrogen Bonding Nonpolar amino acids tend to cluster together in the interior of the Hydrogen bonds form between polar amino acids and water protein, away from water. molecules, stabilizing the protein's structure. Ionic Interactions Disulfide Bridges Ionic bonds form between oppositely charged amino acids, further Covalent bonds formed between cysteine residues, providing stabilizing the protein's shape. additional stability. Quaternary Structure: Multiple Polypeptide Chains The quaternary structure of a protein refers to the arrangement of multiple polypeptide chains into a functional protein complex. These interactions are typically noncovalent and can involve a variety of forces, including hydrophobic interactions, hydrogen bonds, and ionic interactions. Stability Function Quaternary structure enhances The arrangement of subunits stability by providing a larger in quaternary structure can surface area for interactions. facilitate specific functions, such as binding to ligands or catalyzing reactions. Myoglobin: Oxygen Storage in Muscle Myoglobin is a protein found in muscle tissue, specifically in the skeletal muscles of mammals. Its primary function is to store oxygen, making it readily available for muscle cells during periods of high energy demand. Single Chain 1 Myoglobin is a single polypeptide chain. Heme Group 2 Contains a heme group, a porphyrin ring with an iron atom that binds oxygen. Oxygen Storage 3 Stores oxygen in muscle tissue, releasing it when needed.  Hemoglobin: Oxygen Transport in Blood Hemoglobin is a protein found in red blood cells, responsible for transporting oxygen from the lungs to the tissues throughout the body. It is composed of four polypeptide chains, each containing a heme group. 4 4 Subunits Heme Groups Hemoglobin has four subunits: two alpha chains and two beta chains. Each subunit contains a heme group, which binds oxygen. Protein Folding: A Complex Process The folding of a protein from its linear amino acid sequence into its functional three-dimensional structure is a complex process influenced by a variety of factors. These factors include the amino acid sequence itself, interactions with other molecules, and the cellular environment. The amino acid sequence determines the protein's inherent folding potential. Certain amino acids have specific properties, such as The cellular environment, including temperature, pH, and the hydrophobicity or charge, that influence their interactions and the presence of other molecules, can also influence protein folding. overall folding process. 1 2 3 Interactions with other molecules, such as chaperone proteins, can assist in the folding process by preventing misfolding and aggregation. Key Takeaways Proteins are complex molecules with intricate structures that are essential for life. Understanding the different levels of protein structure, from primary to quaternary, provides insight into their function and the processes that govern their formation. Further study in this area is crucial for developing new therapies and addressing various diseases. Amino Acid Sequence The primary structure of a protein is determined by the amino acid sequence. Local Folding Secondary structure involves the formation of alpha helices and beta sheets. 3D Shape Tertiary structure refers to the protein's overall three-dimensional shape. Protein Complexes Quaternary structure involves the assembly of multiple polypeptide chains. The Diverse World of Proteins Proteins are essential biomolecules that play a wide variety of roles in living organisms. From structural support and catalysis to transport and regulation, proteins are involved in virtually every cellular process. This presentation explores the general and specific classifications of proteins, highlighting their diverse structures, functions, and chemical by Steffy Largo reactions. General Classification of Proteins Simple Proteins Conjugated Proteins Derived Proteins Simple proteins consist of only These proteins are formed when a Derived proteins are formed by amino acids and occasional small simple protein combines with a the breakdown of simple or carbohydrate compounds. They non-protein component called a conjugated proteins. They are are the basic building blocks of prosthetic group. Examples often created through physical or more complex proteins. Examples include nucleoproteins, chemical processes and include include albumins, globulins, and glycoproteins, and haemoglobins. denatured proteins and peptides. glutelins. Specific Classifications: Solubility Albumins Globulins These are soluble in Globulins are insoluble in water and dilute salt water but soluble in dilute solutions. They are easily salt solutions. They are coagulated by heat. coagulated by heat. Glutelins Albuminoids These are insoluble in Albuminoids are insoluble water and dilute salt in all neutral solvents. solutions but soluble in They are not coagulated dilute acids and bases. by heat. They are coagulated by heat. Specific Classifications: Composition Nucleoproteins Glycoproteins These proteins are complexed Glycoproteins contain with nucleic acids and are carbohydrate moieties attached crucial for genetic information to the protein backbone, storage and expression. playing roles in cell recognition and signaling. Phosphoproteins Haemoglobins Phosphoproteins have Haemoglobins are responsible phosphate groups attached to for oxygen transport in the their amino acid residues, often blood, containing a heme involved in regulation and prosthetic group that binds signaling processes. oxygen. Specific Classifications: Function Enzymes Structural Proteins Enzymes are biological catalysts Structural proteins provide support that accelerate chemical reactions and shape to cells and tissues, in living organisms, vital for forming the framework of the metabolism. body. Transport Proteins Hormones Transport proteins facilitate the Hormones are chemical movement of molecules across messengers that regulate various cell membranes, ensuring the physiological processes delivery of nutrients and removal throughout the body. of waste. Specific Classifications: Gross Structure 1 Fibrous Proteins Fibrous proteins are long, slender, and often insoluble in water. They play structural roles in cells and tissues, providing support and strength. Examples include collagen, keratin, and elastin. 2 Globular Proteins Globular proteins are compact, spherical, and often soluble in water. They have diverse functions, including catalysis, transport, and regulation. Examples include enzymes, antibodies, and hormones. Chemical Reactions of Proteins: Hydrolysis Acids Acids can break down proteins into smaller peptides and amino acids through a process called hydrolysis. Organic acids, such as acetic acid, are often more effective than mineral acids in this process. Bases Bases can also hydrolyze proteins, causing rapid and complete breakdown. This can lead to the deamination of certain amino acids, where the amino group is removed. Enzymes Enzymes, such as pepsin, are biological catalysts that can specifically hydrolyze proteins. Pepsin, for instance, breaks down proteins into proteoses, peptones, and polypeptides. Chemical Reactions of Proteins: Precipitation Acids Proteins can react with acids due to their free amino groups. This reaction can 1 cause precipitation, forming insoluble complexes. Picric Acid Picric acid is an example of an alkaloidal reagent that can precipitate 2 proteins. It is used in burn treatment to reduce mucous membrane excretion and prevent toxin absorption. Tannic Acid 3 Tannic acid is another alkaloidal reagent used in burn ointments to precipitate proteins and protect wounds. Protein Denaturation: Unfolding the Molecule Definition 1 Denaturation is a process that alters the chemical, physical, and biological properties of a protein, often causing the protein to unfold and lose its functional structure. Consequences 2 Denaturation can destroy the physiological function of a protein. It refers to the disruption of secondary, tertiary, and quaternary structures without breaking the peptide bonds. Reversibility 3 Denaturation can be reversible or irreversible, depending on the severity of the denaturing agent and the protein's resilience. Denaturing Agents: Causes of Protein Unfolding 1 2 Heat Alcohol Heat can disrupt all types of bonds in a protein, leading to Alcohol denatures proteins by forming hydrogen bonds that denaturation. This can be a reversible process at low compete with the naturally occurring hydrogen bonds, causing temperatures or irreversible at higher temperatures. unfolding. It is often used for sterilization and disinfection due to its denaturing effect on proteins. 3 4 Heavy Metal Salts Radiation Heavy metal salts can disrupt salt bridges and disulfide bonds Radiation can also cause irreversible protein denaturation by in proteins, leading to denaturation. This effect is often disrupting hydrogen bonds and hydrophobic interactions, often irreversible, making heavy metals toxic to living organisms. leading to damage and dysfunction in cells and tissues.