Molecular Crowding
Molecular Crowding - Related Videos
10:23
Crowding
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2023
Source: Laboratory of Jonathan Flombaum—Johns Hopkins University Human vision depends on light-sensitive neurons that are arranged in the back of the eye on a tissue called the retina. The neurons, called the rods and cones because of their shapes, are not uniformly distributed on the retina. Instead, there is a region in the center of the retina called the macula where cones are densely packed, and especially so in a central sub-region of the macula called the fovea. Outside the fovea there...
09:14
Improving 2D and 3D Skin In Vitro Models Using Macromolecular Crowding
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Cited by 14 •
2016
We present a protocol to obtain cell-derived matrices rich in extracellular matrix proteins, using macromolecular crowders (MMC). In addition, we present a protocol which incorporates MMC in 3D organotypic skin co-culture generation, which reduces culture time while maintaining maturity of construct.
09:55
Molecular Cloning
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2023
Molecular cloning is a set of methods, which are used to insert recombinant DNA into a vector - a carrier of DNA molecules that will replicate recombinant DNA fragments in host organisms. The DNA fragment, which may be a gene, can be isolated from a prokaryotic or eukaryotic specimen. Following isolation of the fragment of interest, or insert, both the vector and insert must be cut with restriction enzymes and purified. The purified pieces are joined together though a technique called...
12:02
Molecular Evolution of the Tre Recombinase
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Cited by 4 •
2008
Here we report the generation of Tre recombinase through directed, molecular evolution. Tre recombinase recognizes a pre-defined target sequence within the LTR sequences of the HIV-1 provirus, resulting in the excision and eradication of the provirus from infected human cells. While still in its infancy, directed molecular evolution will allow the creation of custom enzymes that will serve as tools of molecular surgery and molecular medicine.
02:00
Molecular Models
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2020
Physical models representing molecular architectures of chemical compounds play essential roles in understanding chemistry. The use of molecular models makes it easier to visualize the structures and shapes of atoms and molecules. Skeletal Model Simpler two-dimensional representations of chemical compounds are accomplished using skeletal models. The illustration shows only the molecular framework or bonds without explicitly showing the atoms. In this representation, many of the carbon atoms...
FAQs
Excluded-volume effects reduce the space and solvent available to reactants. In a densely packed compartment, molecules therefore encounter a physical environment unlike a dilute solution, even when the same biochemical components are present. This change in available volume can modify how often molecules meet and how they behave during biochemical reactions, providing a mechanistic basis for crowding-dependent cellular effects.
Diffusion and molecular association respond to crowding in different but connected ways. Reduced available space can influence how molecules move, while the same spatial constraints can alter the likelihood or behavior of molecular partners associating. Considering both processes is important because cellular reactions depend not only on molecular mobility but also on productive interactions between proteins, nucleic acids, and other polymers.
Protein folding and reaction rates can differ between crowded and dilute settings because surrounding macromolecules change the physical conditions experienced by a protein or reacting molecule. The resulting behavior may not match measurements from simplified laboratory solutions. Accounting for crowding is therefore important when interpreting enzyme function or folding-related observations in environments such as the cytoplasm or cell nucleus.
An effective comparison begins by examining a biochemical process in a dilute laboratory solution and then considering how confinement and densely packed macromolecules could change the same process. Researchers can focus on outcomes such as diffusion, association, folding, or reaction rate. This comparison helps distinguish effects arising from the molecules themselves from effects introduced by the surrounding cellular environment.
Researchers apply molecular crowding to models of cellular organization, gene regulation, enzyme function, and biomolecular assembly. In each case, the principle supplies environmental context that dilute-solution models may omit. Including the occupied volume of proteins, nucleic acids, and other polymers can make descriptions of intracellular processes more representative of conditions in the cell cytoplasm or nucleus.
Within biology, molecular crowding provides a way to connect physical conditions with large-scale cellular behavior. It helps explain why biochemical processes observed in dilute laboratory solutions may differ inside cells, where macromolecules occupy much of the available volume. This perspective is relevant when interpreting cellular organization and building models of how molecules assemble or regulate gene-related processes.