Journal of Biological Chemistry最新文献_第3页

The RecA-NT homology motif in ImuB mediates the interaction with ImuA' which is essential for DNA damage-induced mutagenesis.

IF 4 2区生物学

Journal of Biological Chemistry Pub Date : 2024-12-18 DOI: 10.1016/j.jbc.2024.108108

Joana A Santos, Kęstutis Timinskas, Atondaho A Ramudzuli, Meindert H Lamers, Česlovas Venclovas, Digby F Warner, Sophia J Gessner

{"title":"The RecA-NT homology motif in ImuB mediates the interaction with ImuA' which is essential for DNA damage-induced mutagenesis.","authors":"Joana A Santos, Kęstutis Timinskas, Atondaho A Ramudzuli, Meindert H Lamers, Česlovas Venclovas, Digby F Warner, Sophia J Gessner","doi":"10.1016/j.jbc.2024.108108","DOIUrl":"10.1016/j.jbc.2024.108108","url":null,"abstract":"The mycobacterial mutasome - comprising ImuA', ImuB, and DnaE2 - has been implicated in DNA damage-induced mutagenesis in Mycobacterium tuberculosis. ImuB, which is predicted to enable mutasome function via its interaction with the β clamp, is a catalytically inactive Y-family DNA polymerase. Like some other members of the Y-family, ImuB features a recently identified amino acid motif with homology to the RecA N-terminus (RecA-NT). Given the role of RecA-NT in RecA oligomerization, we hypothesized that ImuB RecA-NT mediates the interaction with ImuA', a RecA homolog of unknown function. Here, we constructed a panel of imuB alleles in which the RecA-NT was removed, or mutated. Our results indicate that RecA-NT is critical for the interaction of ImuB with ImuA'. A region downstream of RecA-NT, ImuB-C, appears to stabilize the ImuB-ImuA' interaction, but its removal does not prevent complex formation. In contrast, replacing two hydrophobic residues of RecA-NT, L378 and V383, disrupts the ImuA'-ImuB interaction. To our knowledge, this is the first experimental evidence suggesting a role for RecA-NT in mediating the interaction between a Y-family member and a RecA homolog.","PeriodicalId":15140,"journal":{"name":"Journal of Biological Chemistry","volume":" ","pages":"108108"},"PeriodicalIF":4.0,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142872253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The physicochemical properties of lipopolysaccharide chemotypes regulate activation of the contact pathway of blood coagulation.

IF 4 2区生物学

Journal of Biological Chemistry Pub Date : 2024-12-18 DOI: 10.1016/j.jbc.2024.108110

André L Lira, Berk Taskin, Cristina Puy, Ravi S Keshari, Robert Silasi, Jiaqing Pang, Joseph E Aslan, Joseph J Shatzel, Christina U Lorentz, Erik I Tucker, Alvin H Schmaier, David Gailani, Florea Lupu, Owen J T McCarty

{"title":"The physicochemical properties of lipopolysaccharide chemotypes regulate activation of the contact pathway of blood coagulation.","authors":"André L Lira, Berk Taskin, Cristina Puy, Ravi S Keshari, Robert Silasi, Jiaqing Pang, Joseph E Aslan, Joseph J Shatzel, Christina U Lorentz, Erik I Tucker, Alvin H Schmaier, David Gailani, Florea Lupu, Owen J T McCarty","doi":"10.1016/j.jbc.2024.108110","DOIUrl":"https://doi.org/10.1016/j.jbc.2024.108110","url":null,"abstract":"Lipopolysaccharide (LPS) is the primary pathogenic factor in Gram-negative sepsis. While the presence of LPS in the bloodstream during infection is associated with disseminated intravascular coagulation, the mechanistic link between LPS and blood coagulation activation remains ill-defined. The contact pathway of coagulation-a series of biochemical reactions that initiates blood clotting when plasma factors XII (FXII) and XI (FXI), prekallikrein (PK) and high molecular weight kininogen (HK) interact with anionic surfaces-has been shown to be activated in Gram-negative septic patients. In this study, using an in vivo baboon model of Gram-negative Escherichia coli sepsis, we observed activation of the contact pathway including FXII, FXI and PK. We examined whether E.coli LPS molecules could binding and activate contact pathway members by quantifying the interaction and activation of either FXII, FXI, or PK with each of three chemotypes of LPS: O111:B4, O26:B6, or Rd2. The LPS chemotypes exhibited distinct physicochemical properties as aggregates and formed complexes with FXII, FXI and PK. The LPS chemotype O26:B6 uniquely promoted the autoactivation of FXII to FXIIa, and in complex with FXIIa, promoted the cleavage of FXI and prekallikrein to generate FXIa and plasma kallikrein, respectively. Furthermore, in complex with the active forms of FXI or prekallikrein, LPS chemotypes were able to regulate the catalytic activity of FXIa and plasma kallikrein, respectively, despite the inability to promote the autoactivation of either zymogen. These data suggest that the procoagulant phenotype of E.coli is influenced by bacterial strain and the physicochemical properties of the LPS chemotypes.","PeriodicalId":15140,"journal":{"name":"Journal of Biological Chemistry","volume":" ","pages":"108110"},"PeriodicalIF":4.0,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142872222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Mechanistic insights into the selective targeting of P2X3 receptor by camlipixant antagonist.

IF 4 2区生物学

Journal of Biological Chemistry Pub Date : 2024-12-18 DOI: 10.1016/j.jbc.2024.108109

Trung Thach, KanagaVijayan Dhanabalan, Prajwal Prabhakarrao Nandekar, Seth Stauffer, Iring Heisler, Sarah Alvarado, Jonathan Snyder, Ramaswamy Subramanian

{"title":"Mechanistic insights into the selective targeting of P2X3 receptor by camlipixant antagonist.","authors":"Trung Thach, KanagaVijayan Dhanabalan, Prajwal Prabhakarrao Nandekar, Seth Stauffer, Iring Heisler, Sarah Alvarado, Jonathan Snyder, Ramaswamy Subramanian","doi":"10.1016/j.jbc.2024.108109","DOIUrl":"https://doi.org/10.1016/j.jbc.2024.108109","url":null,"abstract":"ATP-activated P2X3 receptors play a pivotal role in chronic cough, affecting more than 10% of the population. Despite the challenges posed by the highly conserved structure of P2X receptors, efforts to develop selective drugs targeting P2X3 have led to the development of camlipixant, a potent, selective P2X3 antagonist. However, the mechanisms of receptor desensitization, ion permeation, and structural basis of camlipixant binding to P2X3 remain unclear. Here, we report a cryo-EM structure of camlipixant-bound P2X3, revealing a previously undiscovered selective drug-binding site in the receptor. Our findings also demonstrate that conformational changes in the upper-body domain, including the turret and camlipixant-binding pocket, play a critical role: turret opening facilitates P2X3 channel closure to a radius of 0.7 Å, hindering cation transfer, while turret closure leads to channel opening. Structural and functional studies combined with molecular dynamics simulations provide a comprehensive understanding of camlipixant's selective inhibition of P2X3, offering a foundation for future drug development targeting this receptor.","PeriodicalId":15140,"journal":{"name":"Journal of Biological Chemistry","volume":" ","pages":"108109"},"PeriodicalIF":4.0,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142872201","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Menaquinone-specific turnover by M. tuberculosis cytochrome bd is redox regulated by the Q-loop disulfide bond.

IF 4 2区生物学

Journal of Biological Chemistry Pub Date : 2024-12-18 DOI: 10.1016/j.jbc.2024.108094

Tijn T van der Velden, Kanwal Kayastha, Caspar Y J Waterham, Steffen Brünle, Lars J C Jeuken

{"title":"Menaquinone-specific turnover by M. tuberculosis cytochrome bd is redox regulated by the Q-loop disulfide bond.","authors":"Tijn T van der Velden, Kanwal Kayastha, Caspar Y J Waterham, Steffen Brünle, Lars J C Jeuken","doi":"10.1016/j.jbc.2024.108094","DOIUrl":"https://doi.org/10.1016/j.jbc.2024.108094","url":null,"abstract":"Cytochrome bd from Mycobacterium tuberculosis (Mtbd) is a menaquinol oxidase that has gained interest as an antibiotic target due to its importance in survival under infectious conditions. Mtbd contains a characteristic disulfide bond that has been hypothesized to allow for Mtbd activity regulation at the enzymatic level, possibly helping M. tuberculosis to rapidly adapt to the hostile environment of the phagosome. Here, the role of the disulfide bond and quinone specificity have been determined by reconstitution of a minimal respiratory chain and the single-particle cryo-EM structure in the disulfide-reduced form. Mtbd was shown to be specific for menaquinone, while regulation by reduction of the Q-loop disulfide bond decreased oxidase activity up to 90%. Structural analysis shows that a salt bridge unique to Mtbd keeps the Q-loop partially structured in its disulfide-reduced form, which could facilitate the rapid activation of Mtbd upon exposure to reactive oxygen species. We signify Mtbd as the first redox sensory terminal oxidase and propose that this helps M. tuberculosis in the defence against reactive oxygen species encountered during infection.","PeriodicalId":15140,"journal":{"name":"Journal of Biological Chemistry","volume":" ","pages":"108094"},"PeriodicalIF":4.0,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142872204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Resilience and Charge-Dependent Fibrillation of functional amyloid: Interactions of Pseudomonas Biofilm-Associated FapB and FapC Amyloids.

IF 4 2区生物学

Journal of Biological Chemistry Pub Date : 2024-12-18 DOI: 10.1016/j.jbc.2024.108096

Nimrod Golan, Amit Parizat, Orly Tabachnikov, Eilon Barnea, William P Olsen, Daniel E Otzen, Meytal Landau

{"title":"Resilience and Charge-Dependent Fibrillation of functional amyloid: Interactions of Pseudomonas Biofilm-Associated FapB and FapC Amyloids.","authors":"Nimrod Golan, Amit Parizat, Orly Tabachnikov, Eilon Barnea, William P Olsen, Daniel E Otzen, Meytal Landau","doi":"10.1016/j.jbc.2024.108096","DOIUrl":"https://doi.org/10.1016/j.jbc.2024.108096","url":null,"abstract":"FapC and FapB are biofilm-associated amyloids involved in the virulence of Pseudomonas and other bacteria. We herein demonstrate their exceptional thermal and chemical resilience, suggesting that their biofilm structures might withstand standard sterilization, thereby contributing to the persistence of P. aeruginosa infections. Our findings also underscore the impact of environmental factors on Fap proteins, suggesting that orthologs in different Pseudomonas strains adapt to specific environments and roles. Challenging previous assumptions about a simple nucleation role for FapB in promoting FapC aggregation, the study shows a significant influence of FapC on FapB aggregation. The interaction between these FapB and FapC is intricate: FapB stabilizes FapC fibrils, while FapC slows down FapB fibrillation but can still serve as a cross-seeding template. This complex interplay is key to understanding their roles in bacterial biofilms. Furthermore, the study highlights distinct differences between Fap and E. coli's CsgA (curli) amyloid, where CsgB assumes a simple unidirectional role in nucleating CsgA fibrillation, emphasizing the importance of a comprehensive understanding of various amyloid systems. This knowledge is vital for developing effective intervention strategies against bacterial infections and leveraging the unique properties of these amyloids in technological applications such as novel bio-nanomaterials or protective coatings.","PeriodicalId":15140,"journal":{"name":"Journal of Biological Chemistry","volume":" ","pages":"108096"},"PeriodicalIF":4.0,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142872168","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

ADP-ribosyltransferase-based biocatalysis of non-hydrolyzable NAD+ analogs.

IF 4 2区生物学

Journal of Biological Chemistry Pub Date : 2024-12-18 DOI: 10.1016/j.jbc.2024.108106

Moona Sakari, Rajendra Bhadane, Sujit Kumar, Rita Azevedo, Morteza Malakoutikhah, Ahmadreza Masoumi, Dene R Littler, Harri Härmä, Kari Kopra, Arto T Pulliainen

{"title":"ADP-ribosyltransferase-based biocatalysis of non-hydrolyzable NAD+ analogs.","authors":"Moona Sakari, Rajendra Bhadane, Sujit Kumar, Rita Azevedo, Morteza Malakoutikhah, Ahmadreza Masoumi, Dene R Littler, Harri Härmä, Kari Kopra, Arto T Pulliainen","doi":"10.1016/j.jbc.2024.108106","DOIUrl":"https://doi.org/10.1016/j.jbc.2024.108106","url":null,"abstract":"Enzyme promiscuity is the ability of an enzyme to catalyze an unexpected side reaction in addition to its main reaction. Here, we describe a biocatalytic process to produce non-hydrolyzable NAD+ analogs based on the ADP-ribosyltransferase (ART) activity of pertussis toxin PtxS1 subunit. First, in identical manner to normal catalysis, PtxS1 activates NAD+ to form the reactive oxocarbenium cation. Subsequently, the electrophilic ribose 1' carbon of the oxocarbenium cation is subject of an attack by the nitrogen atom of an amino group coupled to nicotinamide mimicking compounds. The nitrogen atom acts as the nucleophile instead of the natural sulfur atom substrate of the human Gαi protein. The invention builds on structural data indicating the presence of an NAD+ analog, benzamide amino adenine dinucleotide (BaAD), at the NAD+ binding site of PtxS1. This was witnessed upon co-crystallization of PtxS1 with NAD+ and 3-aminobenzamide (3-AB). A pharmacophore-based screening on 3-AB followed by quantum mechanical simulations identified analogs of 3-AB with capacity to react with the oxocarbenium cation. Based on HPLC and mass spectrometry, we confirmed the formation of BaAD by PtxS1, and also identified two new chemical entities. We name the new entities as isoindolone amine adenine dinucleotide (IiaAD), and isoquinolinone amine adenine dinucleotide (IqaAD), the latter being a highly fluorescent compound. The new NAD+ analogs emerge as valuable tools to study the structural biology and enzymology of NAD+ binding and consuming enzymes, such as human poly(ADP-ribose) polymerases (PARPs) and bacterial ART exotoxins, and to advance the ongoing drug development efforts.","PeriodicalId":15140,"journal":{"name":"Journal of Biological Chemistry","volume":" ","pages":"108106"},"PeriodicalIF":4.0,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142872155","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Inositol phosphates dynamically enhance stability, solubility and catalytic activity of mTOR.

IF 4 2区生物学

Journal of Biological Chemistry Pub Date : 2024-12-18 DOI: 10.1016/j.jbc.2024.108095

Lucia E Rameh, John D York, Raymond D Blind

{"title":"Inositol phosphates dynamically enhance stability, solubility and catalytic activity of mTOR.","authors":"Lucia E Rameh, John D York, Raymond D Blind","doi":"10.1016/j.jbc.2024.108095","DOIUrl":"https://doi.org/10.1016/j.jbc.2024.108095","url":null,"abstract":"Mechanistic Target of Rapamycin (mTOR) binds the small metabolite inositol hexakisphosphate (IP6) as shown in structures of mTOR, however it remains unclear if IP6, or any other inositol phosphate species, function as an integral structural element(s) or catalytic regulator(s) of mTOR. Here, we show that multiple, exogenously added inositol phosphate species can enhance the ability of mTOR and mTORC1 to phosphorylate itself and peptide substrates in in vitro kinase reactions, with the higher order phosphorylated species being more potent (IP6=IP5>IP4>>IP3). IP6 increased the VMAX and decreased the apparent KM of mTOR for ATP. Although IP6 did not affect the apparent KM of mTORC1 for ATP, monitoring kinase activity over longer reaction times showed increased product formation, suggesting inositol phosphates stabilize an active form of mTORC1 in vitro. The effects of IP6 on mTOR were reversible, suggesting IP6 bound to mTOR can be exchanged dynamically with the free solvent. Interestingly, we also observed that IP6 could alter mTOR electrophoretic mobility under denaturing conditions and its solubility in the presence of manganese. Together, these data suggest for the first time that multiple inositol phosphate species (IP6, IP5, IP4 and to a lesser extent IP3) can dynamically regulate mTOR and mTORC1 by promoting a stable, more soluble active-state of the kinase. Our data suggest that studies of the dynamics of inositol phosphate regulation of mTOR in cells are well justified.","PeriodicalId":15140,"journal":{"name":"Journal of Biological Chemistry","volume":" ","pages":"108095"},"PeriodicalIF":4.0,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142872187","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Prohibitin 1 tethers lipid membranes and regulates OPA1-mediated membrane fusion. 抑制素 1 可拴住脂质膜并调节 OPA1 介导的膜融合。

IF 4 2区生物学

Journal of Biological Chemistry Pub Date : 2024-12-13 DOI: 10.1016/j.jbc.2024.108076

Tadato Ban, Kimiya Kuroda, Mitsuhiro Nishigori, Keisuke Yamashita, Keisuke Ohta, Takumi Koshiba

{"title":"Prohibitin 1 tethers lipid membranes and regulates OPA1-mediated membrane fusion.","authors":"Tadato Ban, Kimiya Kuroda, Mitsuhiro Nishigori, Keisuke Yamashita, Keisuke Ohta, Takumi Koshiba","doi":"10.1016/j.jbc.2024.108076","DOIUrl":"https://doi.org/10.1016/j.jbc.2024.108076","url":null,"abstract":"Prohibitins (PHBs) are ubiquitously expressed proteins in the mitochondrial inner membrane (MIM) that provide membrane scaffolds for both mitochondrial proteins and phospholipids. Eukaryotic PHB complexes contain two highly homologous PHB subunits, PHB1 and PHB2, which are involved in various cellular processes, including metabolic control through the regulation of mitochondrial dynamics and integrity. Their mechanistic actions at the molecular level, however, particularly those of PHB1, remain poorly understood. To gain insight into the mechanistic actions of PHB1, we established an overexpression system for the full-length recombinant protein using silkworm larvae and characterized its biophysical properties in vitro. Using recombinant PHB1 proteoliposomes reconstituted into MIM-mimicking phospholipids, we found that PHB1 forms an oligomer via its carboxy-terminal coiled-coil region. A proline substitution into the PHB1 coiled-coil collapsed its well-ordered oligomeric state, and its destabilization correlated with mitochondrial morphologic defects. Negative-staining electron microscopy revealed that homotypic PHB1-PHB1 interactions via the coiled-coil also induced liposome tethering with remodeling of the lipid membrane structure. We clarified that PHB1 promotes membrane fusion mediated by optic atrophy 1 (OPA1), a key regulator of MIM fusion. Additionally, the presence of PHB1 reduces the dependency of lipids and OPA1 for completing the fusion process. Our in vitro study provides structural insight into how the mitochondrial scaffold plays a crucial role in regulating mitochondrial dynamics. Modulating the structure and/or function of PHB1 may offer new therapeutic potential, not only for mitochondrial dysfunction but also for other cell-related disorders.","PeriodicalId":15140,"journal":{"name":"Journal of Biological Chemistry","volume":" ","pages":"108076"},"PeriodicalIF":4.0,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142828940","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Enhanced dynamic coupling in a nuclear receptor underlies ligand activity. 核受体的动态耦合增强是配体活性的基础。

IF 4 2区生物学

Journal of Biological Chemistry Pub Date : 2024-12-13 DOI: 10.1016/j.jbc.2024.108081

Tracy Yu, Priscilla Villalona, Sabab Hasan Khan, Noriko Mikeasky, Emily Meinert, Jill Magafas, Thilini Pulahinge, Ameen Bader, C Denise Okafor

{"title":"Enhanced dynamic coupling in a nuclear receptor underlies ligand activity.","authors":"Tracy Yu, Priscilla Villalona, Sabab Hasan Khan, Noriko Mikeasky, Emily Meinert, Jill Magafas, Thilini Pulahinge, Ameen Bader, C Denise Okafor","doi":"10.1016/j.jbc.2024.108081","DOIUrl":"https://doi.org/10.1016/j.jbc.2024.108081","url":null,"abstract":"Bile acids are signaling molecules with critical roles in cholesterol and lipid metabolism, achieved by regulating the transcriptional activity of the farnesoid X receptor (FXR, NR1H4), otherwise known as the bile acid receptor. Modifications to the C6 position of the steroidal core yield bile acid derivatives with 100x improved potency over endogenous bile acids. Prevailing hypotheses suggested increased binding affinity for FXR as the driver for this activity enhancement. Our experimental results contradict this suggestion, motivating us to investigate the underlying mechanisms of enhanced ligand activity. We combined functional assays with over 200 microseconds of simulations, revealing an unexpected role for helix 5 in the allosteric signaling of obeticholic acid (OCA). We uncovered dynamic coupling between adjacent helices 5 and 7, which is uniquely enhanced by the bile acid modification. Ultimately, the enhanced potency of the bile acid analog can be traced to its effect on FXR dynamics. In addition to identifying a previously unknown mechanistic role for helix 5-helix 7 coupling in FXR, these results emphasize the inextricable linkage between the activity of nuclear receptor ligands and their effects on receptor dynamics.","PeriodicalId":15140,"journal":{"name":"Journal of Biological Chemistry","volume":" ","pages":"108081"},"PeriodicalIF":4.0,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142828891","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Mammalian hydroxylation of microbiome-derived obesogen, delta-valerobetaine, to homocarnitine, a 5-carbon carnitine analogue. 哺乳动物将微生物衍生的肥胖原--δ-缬甜菜碱羟基化为 5 碳肉碱类似物--高肉碱。

IF 4 2区生物学

Journal of Biological Chemistry Pub Date : 2024-12-13 DOI: 10.1016/j.jbc.2024.108074

Jaclyn Weinberg, Ken H Liu, Choon-Myung Lee, William J Crandall, André R Cuevas, Samuel A Druzak, Edward T Morgan, Zachery R Jarrell, Eric A Ortlund, Greg S Martin, Grant Singer, Frederick H Strobel, Young-Mi Go, Dean P Jones

{"title":"Mammalian hydroxylation of microbiome-derived obesogen, delta-valerobetaine, to homocarnitine, a 5-carbon carnitine analogue.","authors":"Jaclyn Weinberg, Ken H Liu, Choon-Myung Lee, William J Crandall, André R Cuevas, Samuel A Druzak, Edward T Morgan, Zachery R Jarrell, Eric A Ortlund, Greg S Martin, Grant Singer, Frederick H Strobel, Young-Mi Go, Dean P Jones","doi":"10.1016/j.jbc.2024.108074","DOIUrl":"https://doi.org/10.1016/j.jbc.2024.108074","url":null,"abstract":"The recently discovered microbiome-generated obesogen, δ-valerobetaine (5-(trimethylammonio)pentanoate), is a 5-carbon structural analogue of the carnitine precursor, γ-butyrobetaine. Here, we report that δ-valerobetaine is enzymatically hydroxylated by mammalian γ-butyrobetaine dioxygenase (BBOX) to form 3-hydroxy-5-(trimethylammonio)pentanoate, a 5-carbon analogue of carnitine, which we term homocarnitine. Homocarnitine production by human liver extracts depends upon the required BBOX cofactors, 2-oxoglutarate, Fe2+, and ascorbate. Molecular dynamics simulations show successful docking of δ-valerobetaine and homocarnitine to BBOX, pharmacological inhibition of BBOX prevents homocarnitine production, and transfection of a liver cell line with BBOX substantially increases production. Furthermore, an in vivo isotope tracer study shows the conversion of 13C3-trimethyllysine to 13C3-δ-valerobetaine then 13C3-homocarnitine in mice, confirming the in vivo production of homocarnitine. Functional assays show that carnitine palmitoyltransferase acylates homocarnitine to acyl-homocarnitine, analogous to the reactions for the carnitine shuttle. Studies of mouse tissues and human plasma show widespread distribution of homocarnitine and fatty acyl-homocarnitines. The respective structural similarities of homocarnitine and acyl-homocarnitines to carnitine and acyl-carnitines indicate that homocarnitine could impact multiple sites of carnitine distribution and activity, potentially mediating microbiome-associated obesity and metabolic disorders.","PeriodicalId":15140,"journal":{"name":"Journal of Biological Chemistry","volume":" ","pages":"108074"},"PeriodicalIF":4.0,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142828904","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0