La Trobe University BCH2IBM Lecture Slides PDF

COMMONWEALTH OF AUSTRALIA Copyright Regulations 1969 WARNING This material has been reproduced and communicated to you by or on behalf of La Trobe University pursuant to Part VB of the Copyright Act 1968 (the Act). The material in this...

COMMONWEALTH OF AUSTRALIA Copyright Regulations 1969 WARNING This material has been reproduced and communicated to you by or on behalf of La Trobe University pursuant to Part VB of the Copyright Act 1968 (the Act). The material in this communication may be subject to copyright under the Act. Any further reproduction or communication of this material by you may be the subject of copyright protection under the Act. Do not remove this notice. Slide 1 Re-cap BCH2IBM Module 1 - Introduction Katrina Binger Department of Biochemistry and Genetics Slide 2 Intended Learning Outcomes (ILOs) This lecture only serves as revision of BCH2IBM and is not assessable. Slide 3 Cellular life Slide 4 The central dogma Slide 5 DNA Organised into nucleosomes Long-lived, chemically stable High-fidelity replication; detailed mechanism Slide 6 RNA Flexible Chemically unstable Ribosomal (rRNA), messenger (mRNA), transfer (tRNA) Slide 7 Protein synthesis RNA contains instructions for protein synthesis 3 nucleotides on RNA = codon; matching anticodon on tRNA Different tRNA are covalently linked to specific amino acids Amino acids are joined via peptide bond into polypeptide chains Leu Tyr Met Slide 8 Hierarchical structure of proteins Slide 9 Amino acids Amino acids only differ by the chemical properties of their R-groups Hydrophobic vs. hydrophilic, large/bulky vs small, flexible vs. rigid, charged vs. disulfide Amino acids are known by their: Full name 3-letter abbreviation Single letter code Slide 10 Charged amino acids There are five charged amino acids: Arg, Lys, Asp, Glu & His These amino acids can behave as acids (H+ donors) or bases (H+ acceptors), depending on the solution pH pH can have significant effects on amino acid charge and therefore protein folding & function E.g. Histidine =+1 =+1 =0 Average of species in solution =+2 =0 =-1 +1.5 +0.5 -0.5 Slide 11 Protein folding The folding and 3D shape of a protein is due to chemical interactions between amino acid R-groups. These interactions can be: Hydrophilic (love H2O) vs. hydrophobic (hate H2O) van der Waals (between hydrophobic side chains) Disulfide bonds (between sulfur groups) Ionic or salt bridges (between positive & negative charges) Hydrogen bonds (between H2O) …therefore, single nucleotide substitutions can have a significant effect on how a protein folds and thereby its function Slide 12 Protein structure: secondary α-Helix β-sheet Slide 13 Protein structure: tertiary & quaternary Tertiary: Interactions Quaternary: Interactions between amino acids in the between amino acids in same polypeptide chain different polypeptide chains e.g. Sickle cell anaemia Slide 14 Cellular compartmentalisation Lipids play many roles, but they are especially critical to define the cell and many of their internal structures. Lipid families: fatty acids (building blocks), phospholipids, sphingolipids, glycolipids, waxes (and others) Membranes regulate many biological functions, particularly the transport of proteins within and outside the cell (e.g. endocytosis & exocytosis Slide 15 Signalling Six features of signal transduction: Specific Amplification of signal Modularity (mix & match) Desensitisation Integration of signalling pathways Regulation by localisation Slide 16 Summary BCH2IBM focused on the molecular mechanisms underlying the first part of the central dogma: DNA>RNA>Protein In BCH2MBC, we will continue our understanding of cellular life and the central dogma by investigating the mechanisms underlying Protein>Metabolism, and the effects of this on the cellular and organism phenotype. Slide 17 Resources All BCH2IBM lecture slides are available on the LMS Several chapters in ‘Lehninger Principles of Biochemistry Seventh Edition’ (2017), W. H. Freeman and Company Chapters: 1, 2.1-2.3, 3, 4, 5, 8, 12, 24, 25, 26, 27, 28 Slide 18