Related Experiment Video
Updated: Aug 5, 2026
08:15
Self-Assembly of Gamma-Modified Peptide Nucleic Acids into Complex Nanostructures in Organic Solvent Mixtures
Published on: June 26, 2020
Pectin microgels and their subunit structure
M L Fishman1, P Cooke, B Levaj
1Eastern Regional Research Center, U.S. Department of Agriculture, Philadelphia, Pennsylvania 19118.
Archives of Biochemistry and Biophysics
|April 1, 1992
Summary
Peach fruit pectin forms a hierarchical structure of macromolecular species. These structures assemble into a circular gel network, revealing pectin
Area of Science:
- Food science and polymer chemistry
- Biopolymer characterization
Background:
- Pectin, a complex polysaccharide, is crucial in fruit texture and gel formation.
- Understanding pectin's macromolecular structure is key to controlling its functional properties.
Purpose of the Study:
- To elucidate the macromolecular organization of alkaline-extracted peach fruit pectin.
- To characterize the structural hierarchy and gel network formation of pectin.
Main Methods:
- High-performance size exclusion chromatography (HPSEC) was employed to analyze pectin solutions.
- Transmission electron microscopy (TEM) was used to visualize the pectin gel network structure.
Main Results:
- HPSEC identified at least four aggregated macromolecular pectin species in solution.
- TEM revealed an interconnecting gel network composed of rod-like subunits, approximately 1 micron in diameter.
- Partially dissociated subunits were observed under varying salt concentrations.
Conclusions:
- Peach fruit pectin exhibits a hierarchical assembly of macromolecular species.
- These species form a distinct, interconnected gel network structure.
- The structural integrity of the network is influenced by ionic strength.
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...
01:56Structural Protein Function
Structural proteins are a category of proteins responsible for functions ranging from cell shape and movement to providing support to major structures such as bones, cartilage, hair, and muscles. This group includes proteins such as collagen, actin, myosin, and keratin.
Collagen, the most abundant protein in mammals, is found throughout the body. In connective tissue, such as skin, ligaments, and tendons, it provides tensile strength and elasticity. In bones and teeth, it mineralizes to form...
Collagen, the most abundant protein in mammals, is found throughout the body. In connective tissue, such as skin, ligaments, and tendons, it provides tensile strength and elasticity. In bones and teeth, it mineralizes to form...
01:18Assembly of Cytoskeletal Filaments
Cytoskeletal filaments are polymeric forms of smaller protein subunits. However, individual cytoskeletal filaments may easily disassemble or associate with other similar filaments to form rigid structures. Microfilaments, made of actin monomers, rely on actin-binding proteins to form bundles and create networks of individual actin filaments. Microtubules rely on microtubule-associated proteins (MAPs) to form sturdy cylindrical structures. However, the proteins involved in forming complex...
01:19The Structure of Intermediate Filaments
The intermediate filaments are one of three widely studied cytoskeletal filaments. They are so named as their diameter (10 nm) is in between that of microfilaments (7 nm) and the microtubules (25 nm). These filaments are highly stable and can remain intact when exposed to high salt concentrations and detergents. These filaments are responsible for providing stability and mechanical support to the cells. They also help in cell adhesion and maintaining tissue integrity.
Intermediate filaments...
Intermediate filaments...
00:57Formation of Intermediate Filaments
Intermediate filaments are cytoskeletal proteins with higher tensile strength and flexibility than microfilaments and microtubules. Unlike the other two cytoskeletal proteins, intermediate filament formation lacks the enzymatic activity to hydrolyze nucleotides like ATP and GTP to generate energy for polymerization. Therefore, the formation of intermediate filaments is multistep self-assembly. The involvement of any accessory proteins in intermediate filament formation has not yet been reported.
01:28Peptidoglycan Synthesis
Structure of PeptidoglycanPeptidoglycan is a vital structural component of the bacterial cell wall, providing mechanical strength and shape to the cell. It consists of repeating units of two sugars—N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM)—linked by β-1,4 glycosidic bonds. These sugar chains are cross-linked by short peptide chains, forming a mesh-like polymer that surrounds the bacterial plasma membrane.Cytoplasmic Phase – Precursor SynthesisPeptidoglycan biosynthesis begins in...