SCID 141 - Living Process: From Molecules to Cell Instructor: Kittisak Yokthongwattana, Ph.D. Department of Biochemistry, Faculty of Science, Mahidol University Amino Acids and Proteins
Amino Acids
Stereo Chemistry of Amino Acids
Different Side Chains of Amino Acids
Different Side Chains of Amino Acids
Different Side Chains of Amino Acids
Different Side Chains of Amino Acids
Different Side Chains of Amino Acids
Amino Acid Abbreviation
Amino Acid Abbreviation
Covalent Bond Formation Between Amino Acids – disulfide bond
Protonation States of Amino Acids
Protonation States of Amino Acids
Peptide Bond Formation
Polypeptide Chain – primary structure
Polypeptide Chain Folds Into Secondary Structure
AND ANGLES
Ramachandran plot Image from Voet and Voet, Biochemistry, 4th Edition, 2011
What do AND ANGLES signify? Image from Voet and Voet, Biochemistry, 4th Edition, 2011
Polypeptide Chain Folds Into Secondary Structure – alpha helix
Molecular Interaction stabilizing secondary structure is hydrogen bond Image from Lippincott, Fig. 2.6
Polypeptide Chain Folds Into Secondary Structure – alpha helix
Polypeptide Chain Folds Into Secondary Structure – Beta Sheet
Polypeptide Chain Folds Into Secondary Structure – Beta Sheet
Secondary Structures fold into tertiary structure
Intermolecular Interactions that stabilize tertiary structure Disulfide bond formation Hydrophobic interaction Images from Lippincott, Fig. 2.9, 2.10
Intermolecular Interactions that stabilize tertiary structure Ionic interaction Images from Lippincott, Fig. 2.11
Soluble Protein
Chaperone-Assisted Protein Folding – DnaK/DnaJ SYSTEM
Chaperone-Assisted Protein Folding – GroEL/GroES SYSTEM
Transmembrane protein
Transmembrane protein
Transmembrane protein
Transmembrane protein Aquaporin
Voltage-Gated K+ Channel
Example of Chloride Channel
Quaternary Structure of protein is the assembly of tertiary structures http://upload.wikimedia.org/wikipedia/commons/3/3d/1GZX_Haemoglobin.png
Disulfide bond formation also stabilizes protein quaternary structure
Protein folding signifies functions
Collagen is a triple-helix protein The stability of collagen triple helices rely on a sharp turn of the helix caused by an amino acid called hydroxyproline. Hydroxyproline is produced by hydroxylation of the amino acid proline by the enzyme prolyl hydroxylase following its de novo synthesis (as a post-translational modification). Such reaction, which requires vitamin C, takes place in the lumen of the endoplasmic reticulum. http://en.wikipedia.org/wiki/Hydroxyproline#mediaviewer/File:Hydroxyproline_structure.svg
Actin – Myosin are major proteins in myocytes
Actin – Myosin are major proteins in myocytes
Actin – Myosin are major proteins in myocytes
Myosin motor
Actin
Movement of myosin motor on Actin filament
Immunoglobulin proteins - IgG
Immunoglobulin proteins
Immunoglobulin proteins - IgM
Phagocytosis of an antibody-bound virus by a macrophage
Hemoglobin Hemoglobin Myoglobin
Heme structure within hemoglobin upon Oxygen binding
The Bohr Effect CO2 and H+ ions also are effectors of hemoglobin. In active muscle cells, oxygen is rapidly consumed and carbon dioxide and H+ ions are produced. O2 affinity decreases at lower pH. As hemoglobin moves into a tissue with lower pH, it can more easily unload oxygen. Increase in CO2 concentrations have the same effect. In combination, the effect of pH and CO2 allow nearly 90% of the oxygen bound in the lungs to be unloaded in tissues where it is required.
Structural Basis of the Bohr Effect
BPG Binding Stabilizes the T state
Sickle Cell Anemia