scholarly journals A Novel Lipoate-Protein Ligase, Mhp-LplJ, Is Required for Lipoic Acid Metabolism in Mycoplasma hyopneumoniae

2021 ◽  
Vol 11 ◽  
Author(s):  
Jin Jin ◽  
Huan Chen ◽  
Ning Wang ◽  
Kemeng Zhu ◽  
Huanhuan Liu ◽  
...  
Keyword(s):  
Lipoic Acid ◽  
Acid Metabolism ◽  
Model Organism ◽  
Mycoplasma Hyopneumoniae ◽  
Vital Role ◽  
Metabolism Enzymes ◽  
Glycine Cleavage ◽  
One Carbon Metabolism ◽  
Enzyme Complexes

Lipoic acid is a conserved cofactor necessary for the activation of several critical enzyme complexes in the aerobic metabolism of 2-oxoacids and one-carbon metabolism. Lipoate metabolism enzymes are key for lipoic acid biosynthesis and salvage. In this study, we found that Mycoplasma hyopneumoniae (M. hyopneumoniae) Mhp-Lpl, which had been previously shown to have lipoate-protein ligase activity against glycine cleavage system H protein (GcvH) in vitro, did not lipoylate the lipoate-dependent subunit of dihydrolipoamide dehydrogenase (PdhD). Further studies indicated that a new putative lipoate-protein ligase in M. hyopneumoniae, MHP_RS00640 (Mhp-LplJ), catalyzes free lipoic acid attachment to PdhD in vitro. In a model organism, Mhp-LplJ exhibited lipoate and octanoate ligase activities against PdhD. When the enzyme activity of Mhp-LplJ was disrupted by lipoic acid analogs, 8-bromooctanoic acid (8-BrO) and 6,8-dichlorooctanoate (6,8-diClO), M. hyopneumoniae growth was arrested in vitro. Taken together, these results indicate that Mhp-LplJ plays a vital role in lipoic acid metabolism of M. hyopneumoniae, which is of great significance to further understand the metabolism of M. hyopneumoniae and develop new antimicrobials against it.

scholarly journals Development and retention of a primordial moonlighting pathway of protein modification in the absence of selection presents a puzzle

2018 ◽  
Vol 115 (4) ◽  
pp. 647-655 ◽  
Author(s):  
Xinyun Cao ◽  
Yaoqin Hong ◽  
Lei Zhu ◽  
Yuanyuan Hu ◽  
John E. Cronan
Keyword(s):  
Lipoic Acid ◽  
Protein Modification ◽  
Acid Synthesis ◽  
Covalent Attachment ◽  
Aquifex Aeolicus ◽  
Original Function ◽  
E Coli ◽  
Metabolism Enzymes ◽  
Glycine Cleavage ◽  
H Protein

Lipoic acid is synthesized by a remarkably atypical pathway in which the cofactor is assembled on its cognate proteins. An octanoyl moiety diverted from fatty acid synthesis is covalently attached to the acceptor protein, and sulfur insertion at carbons 6 and 8 of the octanoyl moiety form the lipoyl cofactor. Covalent attachment of this cofactor is required for function of several central metabolism enzymes, including the glycine cleavage H protein (GcvH). InBacillus subtilis, GcvH is the sole substrate for lipoate assembly. Hence lipoic acid-requiring 2-oxoacid dehydrogenase (OADH) proteins acquire the cofactor only by transfer from lipoylated GcvH. Lipoyl transfer has been argued to be the primordial pathway of OADH lipoylation. TheEscherichia colipathway where lipoate is directly assembled on both its GcvH and OADH proteins, is proposed to have arisen later. Because roughly 3 billion years separate the divergence of these bacteria, it is surprising thatE. coliGcvH functionally substitutes for theB. subtilisprotein in lipoyl transfer. Known and putative GcvHs from other bacteria and eukaryotes also substitute forB. subtilisGcvH in OADH modification. Because glycine cleavage is the primary GcvH role in ancestral bacteria that lack OADH enzymes, lipoyl transfer is a “moonlighting” function: that is, development of a new function while retaining the original function. This moonlighting has been conserved in the absence of selection by some, but not all, GcvH proteins. Moreover,Aquifex aeolicusencodes five putative GcvHs, two of which have the moonlighting function, whereas others function only in glycine cleavage.

scholarly journals Assembly of Lipoic Acid on Its Cognate Enzymes: an Extraordinary and Essential Biosynthetic Pathway

2016 ◽  
Vol 80 (2) ◽  
pp. 429-450 ◽  
Author(s):  
John E. Cronan
Keyword(s):  
Lipoic Acid ◽  
Biosynthetic Pathway ◽  
Sequence Similarity ◽  
Pfam Family ◽  
Glycine Cleavage System ◽  
Content Type ◽  
Metabolism Enzymes ◽  
Glycine Cleavage ◽  
State Of Affairs ◽  
Eukaryotic Organisms

SUMMARYAlthough the structure of lipoic acid and its role in bacterial metabolism were clear over 50 years ago, it is only in the past decade that the pathways of biosynthesis of this universally conserved cofactor have become understood. Unlike most cofactors, lipoic acid must be covalently bound to its cognate enzyme proteins (the 2-oxoacid dehydrogenases and the glycine cleavage system) in order to function in central metabolism. Indeed, the cofactor is assembled on its cognate proteins rather than being assembled and subsequently attached as in the typical pathway, like that of biotin attachment. The first lipoate biosynthetic pathway determined was that ofEscherichia coli, which utilizes two enzymes to form the active lipoylated protein from a fatty acid biosynthetic intermediate. Recently, a more complex pathway requiring four proteins was discovered inBacillus subtilis, which is probably an evolutionary relic. This pathway requires the H protein of the glycine cleavage system of single-carbon metabolism to form active (lipoyl) 2-oxoacid dehydrogenases. The bacterial pathways inform the lipoate pathways of eukaryotic organisms. Plants use theE. colipathway, whereas mammals and fungi probably use theB. subtilispathway. The lipoate metabolism enzymes (except those of sulfur insertion) are members of PFAM family PF03099 (the cofactor transferase family). Although these enzymes share some sequence similarity, they catalyze three markedly distinct enzyme reactions, making the usual assignment of function based on alignments prone to frequent mistaken annotations. This state of affairs has possibly clouded the interpretation of one of the disorders of human lipoate metabolism.

The acute transient polymorphic psychosis: a biochemical subtype of the cycloid psychosis

2003 ◽  
Vol 15 (1) ◽  
pp. 38-43 ◽  
Author(s):  
L Pepplinkhuizen ◽  
F M M A van der Heijden ◽  
S Tuinier ◽  
W M A Verhoeven ◽  
D Fekkes
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Metabolism ◽  
Psychotic Disorders ◽  
Acid Metabolism ◽  
Plasma Concentrations ◽  
One Carbon Metabolism ◽  
The One

Background:The pathogenesis of atypical psychoses, in particularly those characterized by polymorphic psychopathology, is hypothesized to be related to disturbances in amino acid metabolism.Objective:In the present study, the role of the amino acid serine was investigated in patients with acute transient polymorphic psychosis.Methods:Patients were loaded with serine and with the amino acids glycine and alanine as controls and subsequently evaluated for the development of psychopathological symptoms. In addition, plasma levels of amino acids were measured.Results:In a subgroup of patients suffering from atypical psychoses, this biochemical challenge resulted in the reappearance of psychedelic symptoms in particular. Furthermore, significantly lower plasma concentrations of serine were found. In vitro experiments revealed a disturbance in the one-carbon metabolism. In another group of patients the loading provoked vegetative symptoms and fatigue.Conclusions:Disturbances in amino acid metabolism may be involved in the emergence of certain psychotic disorders.

scholarly journals Genetic dissection of the mitochondrial lipoylation pathway in yeast

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Laura P. Pietikäinen ◽  
M. Tanvir Rahman ◽  
J. Kalervo Hiltunen ◽  
Carol L. Dieckmann ◽  
Alexander J. Kastaniotis
Keyword(s):  
Lipoic Acid ◽  
Model Organism ◽  
Acid Synthesis ◽  
Fatty Acyl ◽  
Model System ◽  
Genetic Dissection ◽  
Post Translational Modification ◽  
Mitochondrial Fatty Acid ◽  
Glycine Cleavage

Abstract Background Lipoylation of 2-ketoacid dehydrogenases is essential for mitochondrial function in eukaryotes. While the basic principles of the lipoylation processes have been worked out, we still lack a thorough understanding of the details of this important post-translational modification pathway. Here we used yeast as a model organism to characterize substrate usage by the highly conserved eukaryotic octanoyl/lipoyl transferases in vivo and queried how amenable the lipoylation system is to supplementation with exogenous substrate. Results We show that the requirement for mitochondrial fatty acid synthesis to provide substrates for lipoylation of the 2-ketoacid dehydrogenases can be bypassed by supplying the cells with free lipoic acid (LA) or octanoic acid (C8) and a mitochondrially targeted fatty acyl/lipoyl activating enzyme. We also provide evidence that the S. cerevisiae lipoyl transferase Lip3, in addition to transferring LA from the glycine cleavage system H protein to the pyruvate dehydrogenase (PDH) and α-ketoglutarate dehydrogenase (KGD) E2 subunits, can transfer this cofactor from the PDH complex to the KGD complex. In support of yeast as a model system for human metabolism, we demonstrate that the human octanoyl/lipoyl transferases can substitute for their counterparts in yeast to support respiratory growth and protein lipoylation. Like the wild-type yeast enzyme, the human lipoyl transferase LIPT1 responds to LA supplementation in the presence of the activating enzyme LplA. Conclusions In the yeast model system, the eukaryotic lipoylation pathway can use free LA and C8 as substrates when fatty/lipoic acid activating enzymes are targeted to mitochondria. Lip3 LA transferase has a wider substrate specificity than previously recognized. We show that these features of the lipoylation mechanism in yeast are conserved in mammalian mitochondria. Our findings have important implications for the development of effective therapies for the treatment of LA or mtFAS deficiency-related disorders.

scholarly journals Loss of SHMT2 mediates 5-FU chemoresistance by inducing autophagy in colorectal cancer

2019 ◽  
Author(s):  
Jian Chen ◽  
Guangjian Fan ◽  
Chao Xiao ◽  
Xiao Wang ◽  
Yupeng Wang ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Poor Prognosis ◽  
Vital Role ◽  
Serine Hydroxymethyltransferase ◽  
Colorectal Carcinogenesis ◽  
Chemotherapeutic Drug ◽  
Xenograft Models ◽  
One Carbon Metabolism

AbstractSerine hydroxymethyltransferase 2 (SHMT2) plays a vital role in one-carbon metabolism and drives colorectal carcinogenesis. In our study, loss of SHMT2 induced 5-Fluorouracil (5-FU) chemoresistance and was associated with poor prognosis in colorectal cancer (CRC). To elucidate the possible mechanism and generate a strategy to sensitize CRC to 5-FU chemotherapy, we first identified the binding proteins of SHMT2 in cancer cells by mass spectrometry. We found that SHMT2 inhibited autophagy through binding cytoplasmic p53. In fact, SHMT2 prevented cytoplasmic p53 degradation by inhibiting the binding of p53 and HDM2. Under treatment with 5-FU, depletion of SHMT2 promoted autophagy and inhibited apoptosis. Autophagy inhibitors CQ decreased low SHMT2-induced 5-FU resistance in vitro and in vivo. Finally, we enhanced the lethality of 5-FU treatment to CRC cells through the autophagy inhibitor or knockdown of SHMT2 in patient-derived and CRC cell xenograft models. Our findings identified the low SHMT2-induced autophagy on 5-FU resistance in CRC. These results reveal SHMT2-p53 as a novel cancer therapeutic target to reduce chemotherapeutic drug resistance.

scholarly journals Genetic dissection of the mitochondrial lipoylation pathway in yeast

2020 ◽  
Author(s):  
Laura P. Pietikäinen ◽  
M. Tanvir Rahman ◽  
J. Kalervo Hiltunen ◽  
Carol L. Dieckmann ◽  
Alexander J. Kastaniotis
Keyword(s):  
Lipoic Acid ◽  
Model Organism ◽  
Acid Synthesis ◽  
Fatty Acyl ◽  
Model System ◽  
Genetic Dissection ◽  
Post Translational Modification ◽  
Mitochondrial Fatty Acid ◽  
Glycine Cleavage

ABSTRACTBackgroundLipoylation of 2-ketoacid dehydrogenases is essential for mitochondrial function in eukaryotes. While the basic principles of the lipoylation processes have been worked out, we still lack a thorough understanding of the details of this important post-translational modification pathway. Here we used yeast as a model organism to characterize substrate usage by the highly conserved eukaryotic octanoyl/lipoyl transferases in vivo and queried how amenable the lipoylation system is to supplementation with exogenous substrate.ResultsWe show that the requirement for mitochondrial fatty acid synthesis to provide substrates for lipoylation of the 2-ketoacid dehydrogenases can be bypassed by supplying the cells with free lipoic acid (LA) or octanoic acid (C8) and a mitochondrially targeted fatty acyl/lipoyl activating enzyme. We also provide evidence that the S. cerevisiae lipoyl transferase Lip3, in addition to transferring LA from the glycine cleavage system H protein to the pyruvate dehydrogenase (PDH) and α-ketoglutarate dehydrogenase (KGD) E2 subunits, can transfer this cofactor from the PDH complex to the KGD complex. In support of yeast as a model system for human metabolism, we demonstrate that the human octanoyl/lipoyl transferases can substitute for their counterparts in yeast to support respiratory growth and protein lipoylation. Like the wild-type yeast enzyme, the human lipoyl transferase LIPT1 responds to LA supplementation in the presence of the activating enzyme LplA.ConclusionsIn the yeast model system, the eukaryotic lipoylation pathway can use free LA and C8 as substrates when fatty/lipoic acid activating enzymes are targeted to mitochondria. Lip3 LA transferase has a wider substrate specificity than previously recognized. We show that these features of the lipoylation mechanism in yeast are conserved in mammalian mitochondria. Our findings have important implications for the development of effective therapies for the treatment of LA or mtFAS deficiency-related disorders.

Trans-sialidase Associated with Atherosclerosis: Defining the Identity of a Key Enzyme Involved in the Pathology

2019 ◽  
Vol 20 (9) ◽  
pp. 938-941
Author(s):  
Victor Y. Glanz ◽  
Veronika A. Myasoedova ◽  
Andrey V. Grechko ◽  
Alexander N. Orekhov
Keyword(s):  
Acid Metabolism ◽  
Research Subject ◽  
Disease Pathogenesis ◽  
Sialidase Activity ◽  
Ph Values ◽  
Ldl Particles ◽  
Optimum Ph ◽  
Key Enzyme ◽  
St6gal I

Atherosclerosis is associated with the increased trans-sialidase activity, which can be detected in the blood plasma of atherosclerosis patients. The likely involvement in the disease pathogenesis made this activity an interesting research subject and the enzyme that may perform such activity was isolated and characterized in terms of substrate specificity and enzymatic properties. It was found that the enzyme has distinct optimum pH values, and its activity was enhanced by the presence of Ca2+ ions. Most importantly, the enzyme was able to cause atherogenic modification of lowdensity lipoprotein (LDL) particles in vitro. However, the identity of the discovered enzyme remained to be defined. Currently, sialyltransferases, mainly ST6Gal I, are regarded as major contributors to sialic acid metabolism in human blood. In this mini-review, we discuss the possibility that atherosclerosis- associated trans-sialidase does, in fact, belong to the sialyltransferases family.

Smart Gn-Keto Nanohybrid Embedded Topical System for Effective Management of Dermatophytosis

2019 ◽  
Vol 9 (1) ◽  
pp. 21-28
Author(s):  
Nisha Sharma ◽  
Shashikiran Misra
Keyword(s):  
Antifungal Activity ◽  
Fungal Infections ◽  
High Surface ◽  
High Surface Area ◽  
Vital Role ◽  
Common Disease ◽  
Microdilution Method ◽  
Enhanced Solubility ◽  
Bioactive Agents

Background and Objectives: Dermatophytosis (topical fungal infection) is the 4th common disease in the last decade, affecting 20-25% world’s population. Patients of AIDS, cancer, old age senescence, diabetes, cystic fibrosis become more vulnerable to dermatophytosis. The conventional topical dosage proves effective as prophylactic in preliminary stage. In the advanced stage, the therapeutics interacts with healthy tissues before reaching the pathogen site, showing undesirable effects, thus resulting in pitiable patient compliance. The youngest carbon nano-trope “Graphene” is recently used to manipulate bioactive agents for therapeutic purposes. Here, we explore graphene via smart engineering by virtue of high surface area and high payload for therapeutics and developed graphene–ketoconazole nanohybrid (Gn-keto) for potent efficacy towards dermatophytes in a controlled manner. </P><P> Methods: Polymethacrylate derivative Eudragit (ERL100 and ERS 100) microspheres embedded with keto and Gn-keto nanohybrid were formulated and characterized through FTIR, TGA, and SEM. In vitro drug release and antifungal activity of formulated Gn-keto microspheres were assessed for controlled release and better efficacy against selected dermatophytes. </P><P> Results: Presence of numerous pores within the surface of ERL100 microspheres advocated enhanced solubility and diffusion at the site of action. Controlled diffusion across the dialysis membrane was observed with ERS100 microspheres owing to the nonporous surface and poor permeability. Antifungal activity against T. rubrum and M. canis using microdilution method focused on a preeminent activity (99.785 % growth inhibition) of developed nanohybrid loaded microspheres as compared to 80.876% of keto loaded microspheres for T. rubrum. The culture of M. canis was found to be less susceptible to formulated microspheres. Conclusion: Synergistic antifungal activity was achieved by nanohybrid Gn-Keto loaded microspheres against selected topical fungal infections suggesting a vital role of graphene towards fungi.

scholarly journals Quantifying fluorescent glycan uptake to elucidate strain-level variability in foraging behaviors of rumen bacteria

Microbiome ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Leeann Klassen ◽  
Greta Reintjes ◽  
Jeffrey P. Tingley ◽  
Darryl R. Jones ◽  
Jan-Hendrik Hehemann ◽  
...  
Keyword(s):  
Metabolic Pathways ◽  
Ex Vivo ◽  
Rapid Assessment ◽  
Vital Role ◽  
Strain Level ◽  
Metabolic Phenotype ◽  
Specific Cell ◽  
Bacterial Cells ◽  
Carbohydrate Utilization

AbstractGut microbiomes, such as the microbial community that colonizes the rumen, have vast catabolic potential and play a vital role in host health and nutrition. By expanding our understanding of metabolic pathways in these ecosystems, we will garner foundational information for manipulating microbiome structure and function to influence host physiology. Currently, our knowledge of metabolic pathways relies heavily on inferences derived from metagenomics or culturing bacteria in vitro. However, novel approaches targeting specific cell physiologies can illuminate the functional potential encoded within microbial (meta)genomes to provide accurate assessments of metabolic abilities. Using fluorescently labeled polysaccharides, we visualized carbohydrate metabolism performed by single bacterial cells in a complex rumen sample, enabling a rapid assessment of their metabolic phenotype. Specifically, we identified bovine-adapted strains of Bacteroides thetaiotaomicron that metabolized yeast mannan in the rumen microbiome ex vivo and discerned the mechanistic differences between two distinct carbohydrate foraging behaviors, referred to as “medium grower” and “high grower.” Using comparative whole-genome sequencing, RNA-seq, and carbohydrate-active enzyme fingerprinting, we could elucidate the strain-level variability in carbohydrate utilization systems of the two foraging behaviors to help predict individual strategies of nutrient acquisition. Here, we present a multi-faceted study using complimentary next-generation physiology and “omics” approaches to characterize microbial adaptation to a prebiotic in the rumen ecosystem.

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