Textbook Question
Is the bond formed between each pair in Problem 18.76 covalent or noncovalent?
a. Cysteine and cysteine
b. Alanine and leucine
c. Aspartic acid and asparagine
d. Serine and lysine
Ch.18 Amino Acids and Proteins
McMurry8th EditionFundamentals of GOBISBN: 9780134015187
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Table of contents
- Ch.1 Matter and Measurements27
- Ch.2 Atoms and the Periodic Table20
- Ch.3 Ionic Compounds8
- Ch.4 Molecular Compounds23
- Ch.5 Classification & Balancing of Chemical Reactions12
- Ch.6 Chemical Reactions: Mole and Mass Relationships28
- Ch.7 Chemical Reactions: Energy, Rate and Equilibrium64
- Ch.8 Gases, Liquids and Solids24
- Ch.9 Solutions52
- Ch.10 Acids and Bases25
- Ch.11 Nuclear Chemistry22
- Ch.12 Introduction to Organic Chemistry: Alkanes57
- Ch.13 Alkenes, Alkynes, and Aromatic Compounds47
- Ch.14 Some Compounds with Oxygen, Sulfur, or a Halogen50
- Ch.15 Aldehydes and Ketones45
- Ch.16 Amines42
- Ch.17 Carboxylic Acids and Their Derivatives57
- Ch.18 Amino Acids and Proteins82
- Ch.19 Enzymes and Vitamins63
- Ch.20 Carbohydrates44
- Ch.21 The Generation of Biochemical Energy65
- Ch.22 Carbohydrate Metabolism45
- Ch.23 Lipids42
- Ch.24 Lipid Metabolism33
- Ch.25 Protein and Amino Acid Metabolism24
- Ch.26 Nucleic Acids and Protein Synthesis45
Chapter 18, Problem 84d
What is meant by the following terms as they apply to protein structure, and what bonds or molecular interactions stabilize that level of structure?
d. Quaternary structure
Verified step by step guidance1
Understand that the quaternary structure of a protein refers to the arrangement and interaction of multiple polypeptide chains (subunits) in a multi-subunit protein complex. This is the highest level of protein structure.
Recognize that the quaternary structure is stabilized by various types of bonds and interactions between the subunits. These include hydrogen bonds, ionic bonds, hydrophobic interactions, and van der Waals forces.
Note that disulfide bonds (covalent bonds between cysteine residues) can also play a role in stabilizing the quaternary structure in some proteins.
Consider examples of proteins with quaternary structures, such as hemoglobin, which consists of four subunits (two alpha and two beta chains) that work together to transport oxygen.
Understand that the quaternary structure is essential for the protein's biological function, as the arrangement of subunits often determines how the protein interacts with other molecules or performs its role in the cell.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Quaternary Structure
Quaternary structure refers to the highest level of protein organization, where multiple polypeptide chains, or subunits, come together to form a functional protein complex. This arrangement can involve identical or different subunits, and the specific interactions between them are crucial for the protein's overall function.
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3:26
Quaternary Protein Structure Concept 1
Types of Bonds
The stability of quaternary structure is primarily maintained by various types of bonds and interactions, including hydrogen bonds, ionic bonds, hydrophobic interactions, and disulfide bridges. These interactions help to hold the subunits together, ensuring that the protein maintains its functional conformation under physiological conditions.
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Protein Functionality
The quaternary structure is essential for the functionality of many proteins, as it allows for cooperative interactions between subunits, which can enhance the protein's activity. For example, in hemoglobin, the binding of oxygen to one subunit increases the affinity of the other subunits for oxygen, demonstrating how quaternary structure can influence biological activity.
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Related Practice
Textbook Question
What is meant by the following terms as they apply to protein structure, and what bonds or molecular interactions stabilize that level of structure?
a. Primary structure
Textbook Question
What is meant by the following terms as they apply to protein structure, and what bonds or molecular interactions stabilize that level of structure?
b. Secondary structure
Textbook Question
What level of protein structure is determined by the following:
a. Peptide bonds between amino acids?
Textbook Question
What level of protein structure is determined by the following:
b. Hydrogen bonds between backbone carbonyl oxygen atoms and hydrogen atoms attached to backbone nitrogen atoms?
Textbook Question
How do the following noncovalent interactions help to stabilize the tertiary and quaternary structure of a protein? Give an example of a pair of amino acids that could give rise to each interaction.
a. Hydrophobic interactions