Tracking life's first step: Two molecules 'awaken' brand new genome

Within hours after fertilization, a unique genome forms from chromosomes contributed by the egg and sperm. However, this new genome is initially inactive and must be "awakened" to begin the transcription of its DNA and start ...

Turning up the heat on pathogenic bacteria

Pathogenic bacteria come alive at the metabolic level when they enter the warmth of the human gut, firing up genes that encode toxins and other compounds harmful to our bodies. A KAUST-led study shows how a critical bacterial ...

Preventing drugs from being transported from cells

An international research team has investigated the transport mechanism of a bacterial membrane protein using an artificially produced antibody fragment. The transport proteins, called ABC exporters, are present, for instance, ...

Frog fungus fights back

Amphibian populations have been declining around the world for more than 40 years. One culprit is the fungus B. dendrobatidis, which causes the disease chytridiomycosis.

New chemical tool to block endocytosis in plants identified

Plant cells absorb many important substances through a process called endocytosis. In plants, endocytosis is essential for nutrient uptake, passing on cellular signals and plant-microbe interactions. However, the vital nature ...

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Small molecule

In pharmacology and biochemistry, a small molecule is an organic compound that is not a polymer. Biopolymers such as nucleic acids, proteins, and polysaccharides (such as starch or cellulose) are not small molecules, although their constituent monomers—ribo- or deoxyribonucleotides, amino acids, and monosaccharides, respectively—are often considered to be. Very small oligomers are also usually considered small molecules, such as dinucleotides, peptides such as the antioxidant glutathione, and disaccharides such as sucrose.

While small molecules almost always have a lower molecular weight than biopolymers, a very small protein with a defined fold, such as the artificial ten-amino-acid protein chignolin[1], can indeed be smaller than some exceptionally large small molecules such as triglycerides.

Small molecules can have a variety of biological functions, serving as cell signalling molecules, as tools in molecular biology, as drugs in medicine, and in countless other roles. These compounds can be natural (such as secondary metabolites) or artificial (such as antiviral drugs); they may have a beneficial effect against a disease (such as FDA approved drugs) or may be detrimental (such as teratogens and carcinogens).

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