Download Understanding Proteins: Peptide Bonds, Amino Acids, and Protein Structure and more Slides Biology in PDF only on Docsity! Lecture 4: Macromolecules And Protein Structure A large part of modern biology is understanding large molecules like Proteins Docsity.com Chapter 3: Peptide Structure: peptide bonds and side chains Docsity.com Chapter 3: 2nd topic: Peptide Bonding Docsity.com Side chains (R groups) determine 20 different amino acids -Central carbon atom C -Amino group H H N Amino group -Carboxyl group OH C O Carboxyl group R -Side chain (R) H -Hydrogen atom Amino Acid Structure Docsity.com Peptide bonds link Amino Acids together OH H H C C N O R H H C C N O R H H H C C N O R A Polypeptide = long chain of amino acids joined by peptide bonds Dehydration synthesis = losing a water Docsity.com Amino Acids Building Blocks for ALL Proteins Non-Essential Amino Acids Glycine Alanine Aspartate Glutamate Asparagine Glutamine Arginine Tyrosine Systeine Serine Proline Assignment: Look up the essential amino acids Essential Amino Acids Phenylalanine Valine Threonine Tryptophan Isoleucine Methionine Histidine Leucine Lysine Docsity.com Side Chains: “R” H | Glycine CH2 O NH2 Asparagine CH2 SH Cysteine CH2 CH2 O OH Glutamic Acid CH2 CH2 O NH2 Glutamine CH2 CH2 CH2 NH NH NH2 Arginine CH2 O OH Aspartic Acid Docsity.com C CH2 OH Serine CH3 Alanine CH2 CH2 CH2 CH2 NH2 Lysine N H C H CH2 C H2C H2 Proline C HCH2 CH3 CH3 Isoleucine CH2 C H CH3 CH3 Leucine C HCH3 OH Threonine CH2 CH2 S CH3 Methionine C CH2 N C H C H NH Histidine Docsity.com Amino Acids Each AA has a unique 1-letter and 3-letter code identifying it in the Protein’s chain… Docsity.com Each AA has a unique 1-letter or a 3-letter code to identifying the Protein’s AA-chain 3-Letter Code in AA chain Protein AA Chain Sequence The background shadow indicates similar binding or folding function. Single letter code Docsity.com Primary Structure Amino acid sequence Peptide bonding H H H H C C O N R H H C C O N R H H C C O N R H C C O OH R Docsity.com Tertiary Structure = Folding Side Chains (R-groups) Bonds: 1. Hydrogen bonds 2. Disulfide bonds (cysteine) 3. Hydrophobic forces 4. Ionic interactions Docsity.com Quaternary Structure >1 polypeptide chain folded Multiple Proteins Folded Together 1. Hydrogen bonds 2. Disulfide bonds (cysteine) 3. Hydrophobic forces 4. Ionic interactions Bonds: The core histone octamer: from Arents et al. (1991). Docsity.com Proteins are Complex and Specific • The complex primary sequence of amino acids in the protein’s chain can be symbolically represented as a “molecular language” that determines the “meaning” or structure of the protein. Protein structure specifies its function. • Proteins function by binding to and interacting with their substrates to effect chemical reactions, cellular communication, pore formation, catalysis, etc. Docsity.com
