β-glucosyltransferase

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Introductions

β-glucosyltransferases (BGTs) are enzymes that transfer glucosyl groups from UDP-glucose to specific receptor molecules, such as flavonoids, terpenoids and alkaloids. BGTs are widely distributed in nature, including plants, bacteria, fungi and animals, and have many important applications in medicine and industry. β-glucosyltransferases (BGTs) are a family of enzymes that catalyze the transfer of glucosyl groups from UDP-glucose to various acceptor molecules, resulting in the formation of glucosides. The acceptor molecules can be small molecules, such as phenols and terpenoids, or large molecules, such as proteins and lipids. BGTs are involved in various physiological processes, such as plant defense against pathogens, detoxification of xenobiotics, and regulation of cellular signaling pathways.

Structure

The crystal structure of BGTs has been determined by X-ray crystallography. BGTs from different organisms have a conserved fold consisting of two structural domains, an N-terminal domain and a C-terminal domain. the N-terminal domain contains a highly conserved pattern, called the DXD pattern, which is responsible for coordinating the metal ions required for catalysis. the size and sequence of the C-terminal domain varies among BGTs and is thought to play a role in substrate recognition and binding.

Physiological roles

BGTs are involved in various physiological processes in different organisms. In plants, they play a key role in the biosynthesis of secondary metabolites, such as anthocyanins, flavonoids and lignans, which act as pigments, antioxidants and defense compounds. BGTs are also involved in plant-microbe interactions, where they catalyze the glucosylation of phytoalexins, toxic compounds produced by plants in response to infection.

Mechanism

The catalytic mechanism of BGTs involves a two-step process. In the first step, the acceptor molecule binds to the active site of the enzyme, where a conformational change occurs to localize the transfer of the glucosyl group. The second step involves the transfer of the glucosyl group from the UDP-glucose to the acceptor molecule, resulting in the formation of glucoside and UDP. This reaction is thought to involve a covalent intermediate between the glucosyl group and a residue (such as an oxygen or nitrogen atom) on the acceptor molecule. This intermediate is then hydrolyzed, releasing the glucoside and regenerating the enzyme.

Regulation

In plants, BGT activity can be induced by stress, such as pathogen infection or herbivory, leading to increased production of secondary metabolites. In animals, BGT activity can be induced by exposure to xenobiotics, leading to an increase in detoxification.

Applications

• BGTs are used in medicine, where they are used to synthesize prodrugs, where the addition of a glucose group to a drug molecule improves its pharmacokinetic properties, such as solubility and bioavailability.
• BGTs are also used in the synthesis of glycosylated proteins and lipids that can have better properties for therapeutic use.
• Industrially, BGTs are used to produce flavoring compounds and natural sweeteners.
• BGTs are also used to modify small molecules, such as flavonoids and terpenoids, which can have better properties for use in cosmetics, nutritional products and pharmaceuticals.

Clinical significance

BGTs have potential clinical relevance in the treatment of various diseases. For example, glucosylation of certain drugs, such as paclitaxel, has been shown to improve their efficacy and reduce their toxicity. BGTs may also play a role in regulating glucose homeostasis, as glucosylation of proteins and lipids can affect their activity and signaling pathways.