Structural Insights into Ubiquinone Biosynthesis in Membranes

Cheng, Wei; Li, Weikai

doi:10.1126/science.1246774

Cited by 126 publications

(202 citation statements)

References 41 publications

(79 reference statements)

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“…Previous studies had shown the critical role of the Asp-rich motif for aromatic prenyltransferase activity. Thus, mutation in the Asp-rich motif would very likely lead to inactive aromatic prenyltransferases (Ohara et al, 2009;Cheng and Li, 2014). The yeast strain harboring mutated PT1L-At and wild-type PT2-At did not produce any prenylated products, which revealed that PT1L is responsible for at least the first prenylation step in the bitter acid pathway (this result is consistent with a previous report; Tsurumaru et al, 2012).…”

supporting

confidence: 89%

A Heteromeric Membrane-Bound Prenyltransferase Complex from Hop Catalyzes Three Sequential Aromatic Prenylations in the Bitter Acid Pathway

et al. 2015

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Bitter acids (a and b types) account for more than 30% of the fresh weight of hop (Humulus lupulus) glandular trichomes and are well known for their contribution to the bitter taste of beer. These multiprenylated chemicals also show diverse biological activities, some of which have potential benefits to human health. The bitter acid biosynthetic pathway has been investigated extensively, and the genes for the early steps of bitter acid synthesis have been cloned and functionally characterized. However, little is known about the enzyme(s) that catalyze three sequential prenylation steps in the b-bitter acid pathway. Here, we employed a yeast (Saccharomyces cerevisiae) system for the functional identification of aromatic prenyltransferase (PT) genes. Two PT genes (HlPT1L and HlPT2) obtained from a hop trichome-specific complementary DNA library were functionally characterized using this yeast system. Coexpression of codon-optimized PT1L and PT2 in yeast, together with upstream genes, led to the production of bitter acids, but no bitter acids were detected when either of the PT genes was expressed by itself. Stepwise mutation of the aspartate-rich motifs in PT1L and PT2 further revealed the prenylation sequence of these two enzymes in b-bitter acid biosynthesis: PT1L catalyzed only the first prenylation step, and PT2 catalyzed the two subsequent prenylation steps. A metabolon formed through interactions between PT1L and PT2 was demonstrated using a yeast two-hybrid system, reciprocal coimmunoprecipitation, and in vitro biochemical assays. These results provide direct evidence of the involvement of a functional metabolon of membrane-bound prenyltransferases in bitter acid biosynthesis in hop.

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confidence: 89%

A Heteromeric Membrane-Bound Prenyltransferase Complex from Hop Catalyzes Three Sequential Aromatic Prenylations in the Bitter Acid Pathway

et al. 2015

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“…The wide cleft formed by the V-shaped TM helix pair may explain the promiscuous substrate preference of ecPgpB. Similar loading mechanisms of lipid substrates have been proposed for several membrane-integrated enzymes (23,24).…”

Section: Cleft Of Substrate Entrance Is Located In the Membrane-solventsupporting

confidence: 58%

Crystal structure of lipid phosphatase Escherichia coli phosphatidylglycerophosphate phosphatase B

Fan

Jiang

Zhao

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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Membrane-integrated type II phosphatidic acid phosphatases (PAP2s) are important for numerous bacterial to human biological processes, including glucose transport, lipid metabolism, and signaling. Escherichia coli phosphatidylglycerol-phosphate phosphatase B (ecPgpB) catalyzes removing the terminal phosphate group from a lipid carrier, undecaprenyl pyrophosphate, and is essential for transport of many hydrophilic small molecules across the membrane. We determined the crystal structure of ecPgpB at a resolution of 3.2 Å. This structure shares a similar folding topology and a nearly identical active site with soluble PAP2 enzymes. However, the substrate binding mechanism appears to be fundamentally different from that in soluble PAP2 enzymes. In ecPgpB, the potential substrate entrance to the active site is located in a cleft formed by a V-shaped transmembrane helix pair, allowing lateral movement of the lipid substrate entering the active site from the membrane lipid bilayer. Activity assays of point mutations confirmed the importance of the catalytic residues and potential residues involved in phosphate binding. The structure also suggests an induced-fit mechanism for the substrate binding. The 3D structure of ecPgpB serves as a prototype to study eukaryotic PAP2 enzymes, including human glucose-6-phosphatase, a key enzyme in the homeostatic regulation of blood glucose concentrations.T ype II phosphatidic acid phosphatases (PAP2s) are a large family of phosphatases important for lipid metabolism and signaling (1, 2). PAP2 proteins have been found in all life kingdoms from bacteria to mammals. They catalyze dephosphorylation of broad substrates by specifically hydrolyzing phosphoric monoester bonds. Their substrates include variety of phosphorylated carbohydrates, peptides, and lipids. PAP2s are involved in vesicular trafficking, secretion, and endocytosis (e.g., the enzyme phosphatidate phosphatase APP1 in yeast) (3); protein glycosylation [e.g., dolichyl pyrophosphate phosphatase 1 (DOLPP1) in the mouse] (4); energy storage (e.g., triacylglycerol biosynthesis) (5); and stress response (6). In contrast to type I PAP enzymes, which are Mg 2+ -dependent and usually soluble, PAP2 proteins are Mg 2+ -independent, and many of PAP2 enzymes are integral transmembrane (TM) proteins (7). Whereas the soluble branch of PAP2s is called class A nonspecific acid phosphatases (NSAPs) (8), the TM branch of the PAP2 family is also called the lipid phosphatase/phosphotransferase family (2) or lipid phosphate phosphatase family (9). Human glucose-6-phosphatase (G6Pase), the key enzyme in the homeostatic regulation of blood glucose concentrations, belongs to the TM PAP2 subfamily (10). Thus, the TM property is unique to the PAP2 family.In Escherichia coli, undecaprenyl phosphate (C 55 -P), a 55-carbon single-lipid chain phospholipid, serves as a carrier lipid to transfer a variety of phosphate-linked polymers across the periplasmic membrane from the cytosol to the periplasmic space. Recently, the crystal structure of phospho-N-acet...

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“…3D, E). The second line of evidence indicating that GGpp modulates intracellular trafficking of UBIAD1 is provided by structural analyses of archaeal UbiA prenyltransferases, which revealed that isoprenyl substrates are positioned in the membrane-embedded active site between conserved aspartate-rich motifs (NDXXDXXXD and DXXXD) (10,11). A residue corresponding to N102 in Fig.…”

Section: Discussionmentioning

confidence: 99%

Geranylgeranyl-regulated transport of the prenyltransferase UBIAD1 between membranes of the ER and Golgi

Schumacher

Jun

et al. 2016

Journal of Lipid Research

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This article is available online at http://www.jlr.orgUbiA prenyltransferase domain-containing protein-1 (UBIAD1) belongs to the UbiA superfamily of integral membrane prenyltransferases (1). These enzymes contain 8-10 transmembrane helices and catalyze transfer of isoprenyl groups to aromatic acceptors, producing a wide range of molecules such as ubiquinones, hemes, chlorophylls, vitamin E, and vitamin K. In animals, UBIAD1 catalyzes transfer of the 20-carbon geranylgeranyl moiety from geranylgeranyl pyrophosphate (GGpp) to menadione released from plant-derived phylloquinone, thereby generating the vitamin K 2 subtype, menaquinone-4 (MK-4) (2, 3).Mutations in the UBIAD1 gene are associated with Schnyder corneal dystrophy (SCD), an autosomal dominant human eye disease characterized by progressive opacification of the cornea, owing to abnormal accumulation of cholesterol and other lipids (4,5). Systemic dyslipidemia appears to be associated with some, but not all, SCD cases (6, 7). Missense mutations that alter 20 amino acid residues in UBIAD1 have been identified in 50 SCD families (8, 9). Several of these altered amino acids reside within the active site of UBIAD1 (10, 11). A link between UBIAD1 and cholesterol metabolism was first provided by coimmunoprecipitation studies that showed an association of UBIAD1 with the cholesterol biosynthetic enzyme, HMGCoA reductase (8). More recently, we showed that UBIAD1 inhibits sterol-accelerated endoplasmic reticulum (ER)-associated degradation (ERAD) of reductase (12), one of several feedback mechanisms that converge on the enzyme to maintain cholesterol homeostasis (13).Abstract UbiA prenyltransferase domain-containing protein-1 (UBIAD1) utilizes geranylgeranyl pyrophosphate (GGpp) to synthesize the vitamin K 2 subtype menaquinone-4. Previously, we found that sterols trigger binding of UBIAD1 to endoplasmic reticulum (ER)-localized HMG-CoA reductase, the rate-limiting enzyme in synthesis of cholesterol and nonsterol isoprenoids, including GGpp. This binding inhibits sterol-accelerated degradation of reductase, which contributes to feedback regulation of the enzyme. The addition to cells of geranylgeraniol (GGOH), which can become converted to GGpp, triggers release of UBIAD1 from reductase, allowing for its maximal degradation and permitting ER-to-Golgi transport of UBIAD1. Here, we further characterize geranylgeranyl-regulated transport of UBIAD1.

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Structural Insights into Ubiquinone Biosynthesis in Membranes

Cited by 126 publications

References 41 publications

A Heteromeric Membrane-Bound Prenyltransferase Complex from Hop Catalyzes Three Sequential Aromatic Prenylations in the Bitter Acid Pathway

A Heteromeric Membrane-Bound Prenyltransferase Complex from Hop Catalyzes Three Sequential Aromatic Prenylations in the Bitter Acid Pathway

Crystal structure of lipid phosphatase Escherichia coli phosphatidylglycerophosphate phosphatase B

Geranylgeranyl-regulated transport of the prenyltransferase UBIAD1 between membranes of the ER and Golgi

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