Ch.18 Amino Acids and Proteins

McMurry - Fundamentals of General, Organic, and Biological Chemistry 8th Edition

McMurry8th EditionFundamentals of General, Organic, and Biological ChemistryISBN: 9780134015187Not the one you use?Change textbook

McMurry 8th Edition

Ch.18 Amino Acids and Proteins

Problem 24

Chapter 18, Problem 24

Consult the β-sheet in Figure 18.2 and (a) name the bonding responsible for the sheet formation and (b) identify the specific atoms responsible for this bonding.

Verified step by step guidance

Step 1: Understand the structure of a β-sheet. A β-sheet is a common secondary structure in proteins, formed by the alignment of polypeptide chains in a sheet-like arrangement.

Step 2: Identify the type of bonding responsible for the formation of the β-sheet. The bonding involved is hydrogen bonding, which occurs between the backbone atoms of the polypeptide chains.

Step 3: Recognize the specific atoms involved in the hydrogen bonding. In a β-sheet, the hydrogen bonds form between the carbonyl oxygen (C=O) of one amino acid and the amide hydrogen (N-H) of another amino acid in a neighboring chain.

Step 4: Note the orientation of the β-sheet. The polypeptide chains can be arranged in either a parallel or antiparallel configuration, which affects the alignment of the hydrogen bonds.

Step 5: Summarize the findings. The bonding responsible for β-sheet formation is hydrogen bonding, and the specific atoms involved are the carbonyl oxygen and the amide hydrogen from the peptide backbone.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

β-sheet Structure

The β-sheet is a common secondary structure in proteins, characterized by strands of amino acids linked together by hydrogen bonds. These strands can be parallel or antiparallel, influencing the overall stability and properties of the protein. Understanding the arrangement of these strands is crucial for grasping how proteins fold and function.

Hydrogen Bonding

Hydrogen bonds are weak interactions that occur when a hydrogen atom covalently bonded to an electronegative atom, like oxygen or nitrogen, is attracted to another electronegative atom. In the context of β-sheets, these bonds form between the carbonyl oxygen of one amino acid and the amide hydrogen of another, stabilizing the sheet structure. This bonding is essential for maintaining the integrity of protein structures.

Amino Acid Residues

Amino acid residues are the building blocks of proteins, each consisting of an amino group, a carboxyl group, and a unique side chain. In β-sheets, specific atoms from the backbone of these residues, particularly the carbonyl (C=O) and amide (N-H) groups, participate in hydrogen bonding. Identifying these residues is key to understanding the formation and stability of the β-sheet.

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Amino Acid Catabolism: Amino Group Example 2

Related Practice

Textbook Question

For each of the conjugated proteins described, identify to which class of conjugated protein it belongs.

a. Cholesterol is attached to this protein in order to move through the blood system.

Textbook Question

How many ways can four different amino acids be arranged in a peptide so that each peptide is unique?

Textbook Question

Examine the α-helix in Figure 18.1 and determine how many backbone C and N atoms are included in the loop between an amide hydrogen atom and the carbonyl oxygen to which it is hydrogen bonded.

Textbook Question

For each of the conjugated proteins described, identify to which class of conjugated protein it belongs.

b. Ionized zinc is attached to this protein so the protein can function.

Textbook Question

How many amino acid units do these atoms come from? Why are these units planar?

Textbook Question

Complete the following two sentences with either globular or fibrous:

a. Proteins with secondary structure composed primarily of alpha-helix are___________ proteins.