FFP1- Carbohydrates Proteins Lipids PDF

Royal College of Surgeons in Ireland – Medical University of Bahrain FFP1-22: Proteins, Carbohydrates and Lipids Module :FFP1 Code :FFP1-101 Class : MedYear1 semester 1 Lecturer : Dr Jeevan Shetty Date : 26th Sep 2023 Pre-class activity- watch these sho...

Royal College of Surgeons in Ireland – Medical University of Bahrain FFP1-22: Proteins, Carbohydrates and Lipids Module :FFP1 Code :FFP1-101 Class : MedYear1 semester 1 Lecturer : Dr Jeevan Shetty Date : 26th Sep 2023 Pre-class activity- watch these short videos https://www.youtube.com/watch?v=_qf_r5EVP6U&ab_channel=g reatpacificmedia https://www.youtube.com/watch?v=_ExVXeovB6s&ab_channel= WhatsUpDude https://www.youtube.com/watch? v=Sb59aH4gknY&ab_channel=7activestudio  Royal College of Surgeons in Ireland – Medical University of Bahrain Learning Outcomes 1.Outline the classification of amino acids 2.Describe the primary, secondary, tertiary and quaternary structure of proteins 3.Explain the concepts of ‘native conformation’ and post-translational modification of a protein 4.Describe the key structural features of monosaccharides 5.Define the glycosidic bond with the structure of a disaccharide 6.Describe the structure and function of polysaccharides 7.Describe the key structural features of fatty acids and the acylglycerides (mono, di and tri) 8.Distinguish between the classifications of lipids: phospholipids, sphingolipids, sterols and lipoproteins  Proteins, GIHEP FFP-1 Carbohydrates & Lipids CNS BMF YEAR-1 & 2 Endocrin e Cardio Renal Prep for Respiratory SC clinical practice The basic structure of an Amino Chemical properties depend acid on the nature of the side-chain [the R group] R Group Properties: – Polarity – Hydrophobic/philic (water hating/loving) – Acidic (H+ Donor) –ve at neutral pH Amino acid SIDE Chain – Basic (H+ Acceptor) +ve (R) properties at neutral pH AA properties determine how they will behave once have been inserted into a polypeptide 4  CHARACTERISTICS OF THE SIDE CHAINS (R GROUPS) Amino Acids Non-polar Polar Hydrophobic Hydrophilic Aliphatic Aromatic Neutral Basic Acidic (hydrocarbon chain) (ring structure) (Positive charge) (Negative charge) OH Glycine Serine Alanine Threonine Lysine Aspartic acid (Aspartate) Valine Phenylalanine Tyrosine Arginine Glutamic acid (Glutamate) Leucine Tryptophan Asparagine Histidine Isoleucine Glutamine Methionine Cysteine COO- Proline 5 NH3+ Some more characteristics The small amino acids: glycine and alanine The branched amino acids: valine, leucine, isoleucine The sulphur-containing amino acids: cysteine and methionine The amino acid found at a bend in a protein: proline Amino acids that can be phosphorylated: serine, threonine and tyrosine Amino acids that can be glycosylated: asparagine, serine and threonine Amino acid that can be nitrosylated: cysteine 6  Essential Non-essential Essential amino acids Methionine Alanine Arginine* Aspartic acid AAs are also categorised as essential Threonine Asparagine These AAs cannot be synthesised in Tryptophan Cysteine the body Valine Glutamic acid They must come from the diet Some AAs are ‘conditionally’ essential: Isoleucine Glycine their rate of synthesis may not be Leucine Proline sufficient to meet demand under all Phenylalanine Serine conditions and may need to come from Histidine Tyrosine the diet Non-essential amino acids are those Lysine that can be synthesised from other Glutamine* amino acids or precursors *Conditionally essential in children MATT VIL PHLY 7  Primary Protein structure Secondary Tertiary Primary structure Quaternary Amino acids formed into a polypeptide chain Amino acids linked together with peptide bonds This bond is formed between the carboxyl group of one amino acid and the amino group of the next amino acid The peptide bond is C(O) - NH Chain has direction: – Start = amino terminus = N terminus – End = carboxyl terminus = C terminus Secondary structure Examples a helix: collagen Amino acid sequence controls folding a helix: keratin in hair Has a regular repetitive folding pattern Hydrogen bonds stabilise Alpha (a) helix b sheet: silk Beta (b) pleated sheet 9 Tertiary structure- E.g. Myoglobin This is further folding of the polypeptide chain Folding into a globular form Compact folded structure – hydrophobic AAs on the inside Globular protein: – hydrophilic AAs on the outside Combination of secondary structural It stabilised by a wide range elements (a-helices, b- of bonds and interactions sheets) between the side chains of connected by loops Form super-secondary amino acids: structures(domains or – Disulphide bonds (between 2 motifs) cysteines) – Hydrophobic interactions – Ionic bond – Hydrogen bonds Quaternary structure It is the arrangement of protein subunits in a multi-meric protein The 3D arrangement of more than one tertiary polypeptide Consist of 2 or more polypeptide chains Polypeptide may be the same or different Held together by – Non-covalent interactions Eg; – Inter-chain disulphide bonds Hemoglobin Native conformation It is the functional fully folded It determines the biological protein structure function of the protein It is a unique three-dimensional – Catalysis structure determined by – Protection – Primary structure – Regulation – Secondary structure – Signal transduction – Tertiary structure – Storage – Sometimes quaternary – Transport structure Denaturation?  Post-translational modifications (PTM) Phosphorylation: + phosphate on Increases the diversity of serine and/or threonine or the proteome tyrosine residue = Chemical modification of phosphoprotein a protein after translation Glycosylation: + sugar group on A functional group is asparagine or serine or threonine attached to an amino residues = glycoprotein acid Acylation: + fatty acid Results in a change in Ubiquitination: + ubiquitin = protein function death signal Nitrosylation: + NO (nitric oxide) Some Common PTM of proteins 13  A little bit of context: Abnormal protein aggregates can cause disease Results from misfolding of proteins into fibrils Fibrils = amyloid Amyloid can be formed from over 20 proteins Deposition in different tissues Presence of misfolded proteins in the brain: Alzheimer’s Disease (Adapted from Meisenberg and Simmons 3rd ed) 14 What are carbohydrates (saccharide)? They are molecules that contain carbon (C), hydrogen (H), and oxygen (O) atoms A single saccharide is called a monosaccharide Two monosaccharides linked together is a disaccharide An oligosaccharide is a few linked monosaccharides – Can be associated with proteins (glycoproteins) or lipids (glycolipids) Polysaccharides consist of many monosaccharides eg cellulose or glycogen 15 Monosaccharides Simple sugar units Empirical formula = (CH2O)n where n = 3 – 7 carbons n = 3 carbons: triose n = 5 carbons: pentose n = 6 carbons: hexose They are poly- hydroxy aldehydes (aldose) or ketones (ketose) 16  Hexoses (C6H12O6) ISOMERS Aldo group Same chemical formula but different Keto group structures Glucose Fructose These structures are called isomers Dietary sources: Glucose: Fruit juices, starch, glycogen, lactose, maltose, cane sugar Fructose: Fruit juices, honey, cane sugar Galactose: Milk (Lactose) Mannose: Plants and gums Glucose, an aldose Fructose, a ketose 17  H O Monosaccharides like to form a ring: 1C cyclisation H 2 OH 6 3 CH2OH HO H O H 4 OH H 5 OH H H 5 OH 1 b = beta 4 6 CH2OH HO H OH is up, bird in the sky HO 3 2 H In an aldose its all happening at H OH carbon 1 = C1 C1 in aldose = carbonyl carbon 6 CH2OH C1 in cyclised aldose = O anomeric carbon H 5 H Have an alpha anomeric carbon Have a beta anomeric carbon H 4 1 a = alpha HO H OH is down, fish in the sea HO 3 2 In a ketose it all happens at OH carbon 2 = C2 H OH Let's have a 18look at this Disaccharides & glycosidic bond: bond between 2 sugars The name or type of bond depends on – The numbers of the connected carbons – The position of the anomeric hydroxyl group If the –OH group is in the alpha configuration, it is an alpha (a) bond If the –OH group is in the beta configuration, it is a beta (b) bond Example: Lactose = b-galactose + glucose – Bond is between carbon 1 of b-galactose and carbon 4 of glucose: condensation event – Bond (linkage) is b (1→ 4) glycosidic bond Carbohydrates can also bind to non- carbohydrate structures  Purines and pyrimidine bases in nucleic acids  Aromatic rings e.g. in steroids  Proteins: glycoproteins  Lipids: glycolipids  n = 3-12: Oligosaccharides Polysaccharides n > 12 – hundreds: Polysaccharides n > 12 – hundreds 1-6 Variations can occur in the chain Monosaccharides Glycosidic bonds 1-4 Branch points Structure 1-4 Example: Amylopectin branched every 24-30 residues Polysaccharide Functions Storage in animals: – Glycogen: A homopolymer of glucose. Branched every 12-14 residues (1-4, 1-6) Storage in plants: – Starch: A homopolymer of glucose; composed of: Amylopectin (80-85%) branched every 24-30 residues (1-4, 1-6) Amylose (15-20%) non-branched helical structure (1-4) Structure in plants: – Cellulose: Homopolymer of glucose. Long straight chains (β1-4) Structure in invertebrates: – Chitin: Homopolymer of n-acetyl-glucosamine Lipids: Lipids are a heterogeneous group of water-insoluble (hydrophobic) organic molecules The fed and fasting states: creating energy. Functions Major source of energy in the body Structural components of cells and organelles Involved in cellular signaling events e.g. – Steroids – Prostaglandins – Leukotrienes Classification of Lipids [a] Fatty acids and their derivatives prostaglandins leukotrienes [b] Lipids containing glycerol Neutral lipids: mono-, di-, tri-acylglycerol (triglycerides) Charged lipids: Phospholipids [c] Lipids not containing glycerol Steroids Sphingolipids Terpenoids [d] Lipoproteins and lipopolysaccharides Chain lengths of Fatty acids Number before colon = number of carbons in chain Number after colon = numbers and positions of double bonds relative to carboxyl carbon E.g. Arachidonic acid 20:4 (5,8,11,14) – 20 carbon chain – 4 double bonds between carbons 5-6, 8- 9, 11-12 and 14-15 It is also an -6 (n-6) fatty acid: terminal double bond is 6 bonds in from the  carbon Essential FAs (EFAs) Nutritionally essential as we cannot synthesise them Arachidonic Linoleic acid (-6 or omega-6): acid – CH3(CH2)4(CH=CHCH2)2(CH2)6COOH 18:2(n-6) -linolenic acid (-3 or omega-3): – CH3CH2(CH=CHCH2)3(CH2)6COOH 18:3(n-3) EFA deficiency (rare) – Scaly dermatitis (ichthyosis) – Visual and neurologic abnormalities Signalling FAs Prostaglandins (PG) Leukotrienes Part of eicosanoid family Eicosanoids (PUFA -20) Synthesis: arachidonic acid via Synthesis: Arachidonic acid (a 20:4 FA) via COX LOX (lipoxygenase) (cyclooxygenase) Longer half-life (up to 4 hours) Potent Multiple roles Short half-life (seconds) – Inflammatory Multiple roles – Neutrophil adhesion – Inflammatory – Platelet homeostasis 28  Monoacyl, Diacyl & Triacyl glycerol, Monoacyl glycerol – Breakdown product of TAG in fat digestion DAG (Diacylglycerol) – Potent intracellular signaller – Mobilisation of calcium Triglycerides (Triacylglycerols: TAG) - Made up of 3 FAs and glycerol - The principal storage form of energy in the body - Stored in adipose tissue Phospholipids (Phosphoglycerates) Sphingolipids Glycerophospholipid Major component of cell membrane E.g.-Lecithin 30 Steroids Contain a characteristic fused ring system with a hydroxyl or keto group on carbon 3 Major steroid classes – Cholesterol (27 carbons) – Bile acids (24 carbons) – Progesterone and adrenocortical steroids (21 carbons) – Androgens (19 carbons) – Estrogens (18 carbons) Functions of cholesterol Metabolic precursor of Vitamin D Bile-acids Steroid hormones It plays a vital role in the structure of membranes We need a constant supply of cholesterol  Lipoproteins Spherical particles found in plasma that transport lipids, including cholesterol Hydrophobic core of triacylglycerols and cholesteryl esters Phospholipid layer associated with https://www.youtube.com/watch? cholesterol and protein v=qglYWog3o8M&ab_channel=FocusMedica Lipoproteins Classes & Characteristics  Proteins, GIHEP FFP-1 Carbohydrates & Lipids CNS BMF YEAR-1 & 2 Endocrin e Cardio Renal Prep for Respiratory SC clinical practice Summary Amino acid classification Protein structure Primary Secondary Tertiary Quaternary Simple sugars are monosaccharides = building block of carbohydrates Polysaccharides are composed of Medical Sciences by Jeannette Naish​- hundreds to thousands of Chapter 2 to help your learning monosaccharides The building block of lipids is the fatty acid chain More complex lipids have glycerol in their structure The most important sterol is cholesterol