structure of hmg coa HMG - HMG-CoA reductase reductase Unraveling the intricate structure of HMG-CoA

Hmg coaformula 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) is a pivotal molecule in cellular metabolism, acting as a crucial intermediate in several vital biochemical pathways作者：ES Istvan·2000·被引用次数：217—The HMGR monomer reveals a uniquestructurecomprised of three domains (Fig. 3): an N-terminal helical domain (N-domain), a large domain (L-domain) whose .... Understanding its structure is key to comprehending its function, particularly its role as a substrate for the enzyme HMG-CoA reductase, the rate-limiting enzyme in cholesterol biosynthesis. This article delves into the detailed structure of HMG-CoA and the enzyme that interacts with it, drawing upon scientific literature and verified data to provide a comprehensive overview.

HMG-CoA itself is a complex molecule, often described by its chemical formula C27H44N7O20P3S. As its name suggests, it is composed of two main components: the HMG group (3-hydroxy-3-methylglutaryl) and CoA (coenzyme A).The 3D structure of HMG CoAreductaseis shown in figure 1. Active site residues of HMG CoA reductase were obtained from Catalytic site atlas and the residues ... The HMG moiety is a branched 6-carbon chain, featuring a hydroxyl group and a methyl group attached to the third carbon. This is linked via an ester bond to the pantetheine portion of CoA. CoA is a vital coenzyme, playing a central role in cellular metabolism, particularly in the synthesis and oxidation of fatty acids and in the citric acid cycle.

The enzyme HMG-CoA reductase (HMGR) is a key player in the metabolism of HMG-CoA. In humans, the primary isoform of HMG-CoA reductase is a transmembrane protein spanning the endoplasmic reticulum membrane, measuring approximately 888 amino acids long.HMG-CoA reductase Its hydrophobic N-terminal domain contains eight membrane-spanning segments, anchoring it within the ER. Crucially, the catalytic site of HMG-CoA reductase is located in the cytosol, making it accessible to its substrate, HMG-CoA作者：ES Istvan·2000·被引用次数：217—The HMGR monomer reveals a uniquestructurecomprised of three domains (Fig. 3): an N-terminal helical domain (N-domain), a large domain (L-domain) whose ....

Scientific investigations, including the determination of 3D Structures of HMG-CoA Reductase, have provided profound insights into the enzyme's architecture.The 3-hydroxy-3-methylglutaryl coenzyme-A (HMG-CoA ... For instance, Three crystal structures of the catalytic portion of human HMGR have been elucidated, offering detailed views of these structures in complex with HMG-CoA, with the breakdown products HMG and CoA alone, and with HMG, CoA, and NADP+. These studies reveal that the catalytic portion of human HMGR can form tight complexes with its substrates.Crystal structure of the catalytic portion of human HMG-CoA ...

The enzyme's structure is characterized by distinct domains. Research indicates that HMG CoA reductase consists of two distinct domains: a hydrophobic N-terminal domain and a C-terminal catalytic domainhydroxymethylglutaryl-CoA reductase. This catalytic domain has been described as having an unusual fold, comprising a central α helix surrounded by a triangular set of walls of β sheets and α helicesHMG-CoA - an overview | ScienceDirect Topics.

Specific residues within the active site of HMG-CoA reductase are critical for its function.3D Structures of HMG-CoA Reductase3D Structures of HMG-CoA Reductase · 1dq8 - hHMGCR catalytic domain (mutant) +CoA+HMG · 1dq9 - hHMGCR catalytic domain (mutant)+ ... For example, published structural data for HMG-CoA (3-hydroxy-3-methylglutaryl-coenzyme A) reductase highlights the importance of residues in "pocket 1" (such as Ser684, Asp690, Lys691, Lys692) and "pocket 2" (including Glu559) for substrate binding and catalysis.

The enzyme's catalytic mechanism involves the reduction of HMG-CoA to mevalonate. This is a four-electron reduction, requiring two molecules of NAD(P)H as the reducing agent. HMG-CoA is then reduced by HMG-CoA reductase (HMGR) to generate mevalonate. This process is fundamental for the synthesis of sterols, which contain a core cyclopentanoperhydrophenanthrene ring system (four fused rings, predominantly six-carbon rings).

Beyond its role in cholesterol biosynthesis, HMG-CoA is also an intermediate in the ketogenesis pathway. Moreover, understanding the structure of HMG-CoA and its interaction with HMG-CoA reductase is crucial for the development of therapeutic agents. HMG-CoA reductase inhibitors, commonly known as statins, are a class of drugs that effectively lower cholesterol levels by blocking this enzyme. The Complex of the catalytic portion of human HMG-COA reductase with atorvastatin, a well-known statin, provides a prime example of how structural information aids in drug design. This complex illustrates how the drug molecule fits within the enzyme's active site, inhibiting its activity.

Further research has explored the structure of HMG-CoA reductase in various organisms, including archaea and plants like *Arabidopsis thaliana* (AtHMG1). These comparative studies reveal variations in active site architecture, such as the wider active site observed in AtHMG1 compared to structures from non-plant organisms, offering insights into evolutionary adaptation and potential drug targeting strategies for different species.

In summary, the structure of HMG-CoA and its associated enzyme, HMG-CoA reductase, are intricate molecular architectures vital for numerous biological processes.Structure and mechanisms of action of HMG-CoA reductase ... From its chemical composition as 3-hydroxy-3-methylglutaryl-CoA to its role in complex metabolic pathways and its significance in pharmaceutical development, the ongoing exploration of these structures continues to deepen our understanding of human health and disease. The availability of detailed 3D Structures of HMG-CoA Reductase and insights into the enzyme's domain organization and active site residues provide a robust foundation built on extensive research and verifiable information.