Related Experiment Video
Updated: Jun 10, 2026
11:27
X-Ray Crystallography to Study the Oligomeric State Transition of the Thermotoga maritima M42 Aminopeptidase TmPep1050
Published on: May 13, 2020
X-ray crystallographic structure of an artificial beta-sheet dimer
Omid Khakshoor1, Aaron J Lin, Tyler P Korman
1Department of Chemistry, University of California, Irvine, California 92697-2025, USA.
Journal of the American Chemical Society
|July 31, 2010
Summary
Researchers designed a cyclic peptide that mimics protein beta-sheet dimers. X-ray crystallography revealed its structure, showing self-assembly into higher-order structures, offering insights into protein mimicry.
Area of Science:
- Structural biology
- Peptide chemistry
- Supramolecular chemistry
Background:
- Proteins often form dimers through beta-sheet interactions.
- Designing synthetic peptides to mimic these structures is a key challenge.
- Understanding these mimics can provide insights into protein folding and function.
Purpose of the Study:
- To determine the X-ray crystallographic structure of a designed cyclic beta-sheet peptide.
- To investigate its ability to form dimers mimicking protein structures.
- To analyze the self-assembly behavior of these peptide dimers.
Main Methods:
- X-ray crystallography was used to determine the detailed structure of the cyclic peptide.
- The peptide incorporates specific amino acids (Hao) and turn units (delta-linked ornithine) to induce beta-sheet formation.
- Molecular modeling was employed to study higher-order self-assembly.
Main Results:
- A 54-membered macrocyclic peptide (1a) was successfully designed and its structure elucidated.
- The peptide forms a well-defined hydrogen-bonded dimer that mimics protein beta-sheet dimers.
- The dimers self-assemble into a barrel-shaped trimer of dimers in the solid state.
Conclusions:
- The designed cyclic peptide effectively mimics protein beta-sheet dimer structures.
- The specific amino acid and turn units are crucial for templating beta-sheet structure and dimerization.
- The observed self-assembly provides a model for related peptides in solution.
Related Concept Videos
02:15Protein and Protein Structure
Proteins are one of the most abundant organic molecules in living systems and have the most diverse range of functions of all macromolecules. Proteins may be structural, regulatory, contractile, or protective. They may serve in transport, storage, or membranes; or they may be toxins or enzymes. Their structures, like their functions, vary greatly. They are all, however, amino acid polymers arranged in a linear sequence.
A protein's shape is critical to its function. For example, an enzyme can...
A protein's shape is critical to its function. For example, an enzyme can...
01:22Protein Folding
Overview
01:25Protein Folding
Proteins are chains of amino acids linked together by peptide bonds. Upon synthesis, a protein folds into a three-dimensional conformation, critical to its biological function. Interactions between its constituent amino acids guide protein folding, and hence the protein structure is primarily dependent on its amino acid sequence.
Protein Structure Is Critical to Its Biological Function
Proteins perform a wide range of biological functions such as catalyzing chemical reactions, providing...
Protein Structure Is Critical to Its Biological Function
Proteins perform a wide range of biological functions such as catalyzing chemical reactions, providing...
01:13Protein Organization
Overview
01:24Protein Organization
Proteins are polymers of amino acid residues. They are versatile and responsible for different cellular functions, including DNA replication, molecular transport, catalysis, and structural support. Proteins have a hierarchical structure comprising at least three levels of organization: primary, secondary, and tertiary structure. Some large proteins have a quaternary structure where individual protein subunits are linked together.
The primary structure of a protein is its amino acid sequence.
The primary structure of a protein is its amino acid sequence.
03:03Amyloid Fibrils
Amyloid fibrils are aggregates of misfolded proteins. Under most circumstances, misfolded proteins are either refolded by chaperone proteins or degraded by the proteasome. However, in the case of a mutation or a disease, these proteins can accumulate to form large clusters and often further assemble to form elongated fibers, called fibrils.
Amyloid deposits were observed as early as 1639 in the liver and the spleen. In 1854, Rudolph Virchow performed iodine staining, normally used to...
Amyloid deposits were observed as early as 1639 in the liver and the spleen. In 1854, Rudolph Virchow performed iodine staining, normally used to...