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Semenovich DS, Andrianova NV, Zorova LD, Pevzner IB, Abramicheva PA, Elchaninov AV, Markova OV, Petrukhina AS, Zorov DB, Plotnikov EY. Fibrosis Development Linked to Alterations in Glucose and Energy Metabolism and Prooxidant-Antioxidant Balance in Experimental Models of Liver Injury. Antioxidants (Basel) 2023; 12:1604. [PMID: 37627599 PMCID: PMC10451385 DOI: 10.3390/antiox12081604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 08/03/2023] [Accepted: 08/10/2023] [Indexed: 08/27/2023] Open
Abstract
The development of liver fibrosis is one of the most severe and life-threatening outcomes of chronic liver disease (CLD). For targeted therapy of CLD, it is highly needed to reveal molecular targets for normalizing metabolic processes impaired in damaged liver and associated with fibrosis. In this study, we investigated the morphological and biochemical changes in rat liver models of fibrosis induced by chronic administration of thioacetamide, carbon tetrachloride, bile duct ligation (BDL), and ischemia/reperfusion (I/R), with a specific focus on carbohydrate and energy metabolism. Changes in the levels of substrates and products, as well as enzyme activities of the major glucose metabolic pathways (glycolysis, glucuronidation, and pentose phosphate pathway) were examined in rat liver tissue after injury. We examined key markers of oxidative energy metabolism, such as the activity of the Krebs cycle enzymes, and assessed mitochondrial respiratory activity. In addition, pro- and anti-oxidative status was assessed in fibrotic liver tissue. We found that 6 weeks of exposure to thioacetamide, carbon tetrachloride, BDL or I/R resulted in a decrease in the activity of glycolytic enzymes, retardation of mitochondrial respiration, elevation of glucuronidation, and activation of pentose phosphate pathways, accompanied by a decrease in antioxidant activity and the onset of oxidative stress in rat liver. Resemblance and differences in the changes in the fibrosis models used are described, including energy metabolism alterations and antioxidant status in the used fibrosis models. The least pronounced changes in glucose metabolism and mitochondrial functions in the I/R and thioacetamide models were associated with the least advanced fibrosis. Ultimately, liver fibrosis significantly altered the metabolic profile in liver tissue and the flux of glucose metabolic pathways, which could be the basis for targeted therapy of liver fibrosis in CLD caused by toxic, cholestatic, or I/R liver injury.
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Affiliation(s)
- Dmitry S. Semenovich
- A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119992 Moscow, Russia
| | - Nadezda V. Andrianova
- A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119992 Moscow, Russia
| | - Ljubava D. Zorova
- A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119992 Moscow, Russia
- V.I. Kulakov National Medical Research Center for Obstetrics, Gynecology and Perinatology, Ministry of Healthcare of Russian Federation, 117198 Moscow, Russia
| | - Irina B. Pevzner
- A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119992 Moscow, Russia
- V.I. Kulakov National Medical Research Center for Obstetrics, Gynecology and Perinatology, Ministry of Healthcare of Russian Federation, 117198 Moscow, Russia
| | - Polina A. Abramicheva
- A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119992 Moscow, Russia
| | - Andrey V. Elchaninov
- Avtsyn Research Institute of Human Morphology of Federal State Budgetary Scientific Institution “Petrovsky National Research Centre of Surgery”, 117418 Moscow, Russia
| | - Olga V. Markova
- A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119992 Moscow, Russia
| | - Aleksandra S. Petrukhina
- K.I. Skryabin Moscow State Academy of Veterinary Medicine and Biotechnology, 109472 Moscow, Russia
| | - Dmitry B. Zorov
- A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119992 Moscow, Russia
- V.I. Kulakov National Medical Research Center for Obstetrics, Gynecology and Perinatology, Ministry of Healthcare of Russian Federation, 117198 Moscow, Russia
| | - Egor Y. Plotnikov
- A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119992 Moscow, Russia
- V.I. Kulakov National Medical Research Center for Obstetrics, Gynecology and Perinatology, Ministry of Healthcare of Russian Federation, 117198 Moscow, Russia
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2
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Chandrasekaran R, Mathieu C, Sheth R, Cheng AP, Fong D, McCormack R, El-Gabalawy H, Alishetty S, Paige M, Hoemann CD. UDP-glucose dehydrogenase (UGDH) activity is suppressed by peroxide and promoted by PDGF in fibroblast-like synoviocytes: Evidence of a redox control mechanism. PLoS One 2022; 17:e0274420. [PMID: 36107941 PMCID: PMC9477357 DOI: 10.1371/journal.pone.0274420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 08/29/2022] [Indexed: 11/18/2022] Open
Abstract
UDP-glucose dehydrogenase (UGDH) generates essential precursors of hyaluronic acid (HA) synthesis, however mechanisms regulating its activity are unclear. We used enzyme histostaining and quantitative image analysis to test whether cytokines that stimulate HA synthesis upregulate UGDH activity. Fibroblast-like synoviocytes (FLS, from N = 6 human donors with knee pain) were cultured, freeze-thawed, and incubated for 1 hour with UDP-glucose, NAD+ and nitroblue tetrazolium (NBT) which allows UGDH to generate NADH, and NADH to reduce NBT to a blue stain. Compared to serum-free medium, FLS treated with PDGF showed 3-fold higher UGDH activity and 6-fold higher HA release, but IL-1beta/TGF-beta1 induced 27-fold higher HA release without enhancing UGDH activity. In selected proliferating cells, UGDH activity was lost in the cytosol, but preserved in the nucleus. Cell-free assays led us to discover that diaphorase, a cytosolic enzyme, or glutathione reductase, a nuclear enzyme, was necessary and sufficient for NADH to reduce NBT to a blue formazan dye in a 1-hour timeframe. Primary synovial fibroblasts and transformed A549 fibroblasts showed constitutive diaphorase/GR staining activity that varied according to supplied NADH levels, with relatively stronger UGDH and diaphorase activity in A549 cells. Unilateral knee injury in New Zealand White rabbits (N = 3) stimulated a coordinated increase in synovial membrane UGDH and diaphorase activity, but higher synovial fluid HA in only 2 out of 3 injured joints. UGDH activity (but not diaphorase) was abolished by N-ethyl maleimide, and inhibited by peroxide or UDP-xylose. Our results do not support the hypothesis that UGDH is a rate-liming enzyme for HA synthesis under catabolic inflammatory conditions that can oxidize and inactivate the UGDH active site cysteine. Our novel data suggest a model where UGDH activity is controlled by a redox switch, where intracellular peroxide inactivates, and high glutathione and diaphorase promote UGDH activity by maintaining the active site cysteine in a reduced state, and by recycling NAD+ from NADH.
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Affiliation(s)
- Ramya Chandrasekaran
- Department of Bioengineering, George Mason University, Manassas, Virginia, United States of America
| | - Colleen Mathieu
- Institute of Biomedical Engineering, Polytechnique Montréal, Montréal, QC, Canada
- Department of Chemical Engineering, Polytechnique Montréal, Montréal, QC, Canada
| | - Rishi Sheth
- Department of Bioengineering, George Mason University, Manassas, Virginia, United States of America
| | - Alexandre P. Cheng
- Department of Chemical Engineering, Polytechnique Montréal, Montréal, QC, Canada
| | - David Fong
- Institute of Biomedical Engineering, Polytechnique Montréal, Montréal, QC, Canada
| | - Robert McCormack
- Department of Orthopedic Surgery, University of British Columbia, Vancouver, BC, Canada
| | - Hani El-Gabalawy
- Department of Medicine and Immunology, University of Manitoba, Winnipeg, MB, Canada
| | - Suman Alishetty
- Department of Bioengineering, George Mason University, Manassas, Virginia, United States of America
| | - Mikell Paige
- Department of Chemistry & Biochemistry, George Mason University, Manassas, Virginia, United States of America
| | - Caroline D. Hoemann
- Department of Bioengineering, George Mason University, Manassas, Virginia, United States of America
- Institute of Biomedical Engineering, Polytechnique Montréal, Montréal, QC, Canada
- Department of Chemical Engineering, Polytechnique Montréal, Montréal, QC, Canada
- * E-mail:
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3
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Transcriptomic Changes in Internode Explants of Stinging Nettle during Callogenesis. Int J Mol Sci 2021; 22:ijms222212319. [PMID: 34830202 PMCID: PMC8618292 DOI: 10.3390/ijms222212319] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 11/09/2021] [Accepted: 11/10/2021] [Indexed: 12/23/2022] Open
Abstract
Callogenesis, the process during which explants derived from differentiated plant tissues are subjected to a trans-differentiation step characterized by the proliferation of a mass of cells, is fundamental to indirect organogenesis and the establishment of cell suspension cultures. Therefore, understanding how callogenesis takes place is helpful to plant tissue culture, as well as to plant biotechnology and bioprocess engineering. The common herbaceous plant stinging nettle (Urtica dioica L.) is a species producing cellulosic fibres (the bast fibres) and a whole array of phytochemicals for pharmacological, nutraceutical and cosmeceutical use. Thus, it is of interest as a potential multi-purpose plant. In this study, callogenesis in internode explants of a nettle fibre clone (clone 13) was studied using RNA-Seq to understand which gene ontologies predominate at different time points. Callogenesis was induced with the plant growth regulators α-napthaleneacetic acid (NAA) and 6-benzyl aminopurine (BAP) after having determined their optimal concentrations. The process was studied over a period of 34 days, a time point at which a well-visible callus mass developed on the explants. The bioinformatic analysis of the transcriptomic dataset revealed specific gene ontologies characterizing each of the four time points investigated (0, 1, 10 and 34 days). The results show that, while the advanced stage of callogenesis is characterized by the iron deficiency response triggered by the high levels of reactive oxygen species accumulated by the proliferating cell mass, the intermediate and early phases are dominated by ontologies related to the immune response and cell wall loosening, respectively.
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Zhang S, Cao L, Sun X, Yu J, Xu X, Chang R, Suo J, Liu G, Xu Z, Qu C. Genome-wide analysis of UGDH genes in Populus trichocarpa and responsiveness to nitrogen treatment. 3 Biotech 2021; 11:149. [PMID: 33732570 DOI: 10.1007/s13205-021-02697-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 02/16/2021] [Indexed: 12/20/2022] Open
Abstract
Plant UDP-glucose 6-dehydrogenase (UGDH) is an important enzyme for the formation of hemicellulose and pectin. Previous studies on UGDH have primarily focused on the biosynthesis of cell wall polysaccharides, while few studies have focused on their regulation by exogenous nitrogen. In the present study, four genes encoding PtUGDH proteins were analyzed by bioinformatics methods. And, the expression profiles of PtUGDH genes under different nitrogen treatments were evaluated with qRT-PCR. The results showed that PtUGDHs have conserved NAD coenzyme binding motif GAGYVGG and the catalytic motif GFGGSCFQKDIL. According to the phylogenetic analysis, PtUGDHs were divided into two subgroups. PtUGDH3 and PtUGDH4 were closely related to AtUGDH1 (important for normal development of Arabidopsis cell wall structure). Chromosomal distribution and genome synteny analysis revealed four segmental-duplicated gene pairs on chr4, 8, 10 and 17. Tissue-specific data from PlantGenIE showed that PtUGDH3 and PtUGDH4 were highly expressed in stems. The qRT-PCR detection showed that the expression of PtUGDH3 in the lower stem and PtUGDH2 of upper leaves were significantly increased induced by low ammonium or nitrate condition. This comprehensive analysis of the UGDH family in poplar provides new insights into their regulation by nitrogen, and would increase our understanding of the roles of UGDHs in hemicellulose and pectin biosynthesis in the cell wall and during poplar development. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1007/s13205-021-02697-9.
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Riegert AS, Raushel FM. Functional and Structural Characterization of the UDP-Glucose Dehydrogenase Involved in Capsular Polysaccharide Biosynthesis from Campylobacter jejuni. Biochemistry 2021; 60:725-734. [PMID: 33621065 DOI: 10.1021/acs.biochem.0c00953] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Campylobacter jejuni is a pathogenic organism that can cause campylobacteriosis in children and adults. Most commonly, campylobacter infection is brought on by consumption of raw or undercooked poultry, unsanitary drinking water, or pet feces. Surrounding the C. jejuni bacterium is a coat of sugar molecules known as the capsular polysaccharide (CPS). The capsular polysaccharide can be very diverse among the different strains of C. jejuni, and this diversity is considered important for evading the host immune system. Modifications to the CPS of C. jejuni NCTC 11168 include O-methylation, phosphoramidylation, and amidation of glucuronate with either serinol or ethanolamine. The enzymes responsible for amidation of glucuronate are currently unknown. In this study, Cj1441, an enzyme expressed from the CPS biosynthetic gene cluster in C. jejuni NCTC 11168, was shown to catalyze the oxidation of UDP-α-d-glucose into UDP-α-d-glucuronic acid with NAD+ as the cofactor. No amide products were found in an attempt to determine whether the putative thioester intermediate formed during the oxidation of UDP-glucose by Cj1441 could be captured in the presence of added amines. The three-dimensional crystal structure of Cj1441 was determined in the presence of NAD+ and UDP-glucose bound in the active site of the enzyme (Protein Data Bank entry 7KWS). A more thorough bioinformatic analysis of the CPS gene cluster suggests that the amidation activity is localized to the t-terminal half of Cj1438, a bifunctional enzyme that is currently annotated as a sugar transferase.
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Affiliation(s)
- Alexander S Riegert
- Department of Biochemistry & Biophysics, Texas A&M University, College Station, Texas 77843, United States
| | - Frank M Raushel
- Department of Biochemistry & Biophysics, Texas A&M University, College Station, Texas 77843, United States.,Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
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Jia T, Ge Q, Zhang S, Zhang Z, Liu A, Fan S, Jiang X, Feng Y, Zhang L, Niu D, Huang S, Gong W, Yuan Y, Shang H. UDP-Glucose Dehydrogenases: Identification, Expression, and Function Analyses in Upland Cotton ( Gossypium hirsutum). Front Genet 2021; 11:597890. [PMID: 33505427 PMCID: PMC7831515 DOI: 10.3389/fgene.2020.597890] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Accepted: 11/27/2020] [Indexed: 11/17/2022] Open
Abstract
UDP-glucose dehydrogenase (UGD; EC1.1.1.22) is a NAD+-dependent enzyme that catalyzes the two-fold oxidation of UDP-glucose (UDP-Glc) to produce UDP-glucuronic acid and plays an important role in plant cell wall synthesis. A total of 42 UGD genes from four Gossypium genomes including G. hirsutum, G. arboretum, G. barbadense, and G. raimondii were identified and found that the UGD gene family has conservative evolution patterns in gene structure and protein domain. The growth of fibers can be effectively promoted after adding the UDP-Glc to the medium, and the GhUGD gene expression enhanced. In addition, the transgenic Arabidopsis lines over-expressing GH_D12G1806 had longer root lengths and higher gene expression level than the wild-type plants of Columbia-0. These results indicated that UGD may play important roles in cotton fiber development and has a guiding significance for dissecting fiber development mechanism.
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Affiliation(s)
- Tingting Jia
- State Key Laboratory of Cotton Biology, Key Laboratory of Biological and Genetic Breeding of Cotton, The Ministry of Agriculture, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, China
| | - Qun Ge
- State Key Laboratory of Cotton Biology, Key Laboratory of Biological and Genetic Breeding of Cotton, The Ministry of Agriculture, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, China
| | - Shuya Zhang
- State Key Laboratory of Cotton Biology, Key Laboratory of Biological and Genetic Breeding of Cotton, The Ministry of Agriculture, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, China
| | - Zhen Zhang
- State Key Laboratory of Cotton Biology, Key Laboratory of Biological and Genetic Breeding of Cotton, The Ministry of Agriculture, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, China
| | - Aiying Liu
- State Key Laboratory of Cotton Biology, Key Laboratory of Biological and Genetic Breeding of Cotton, The Ministry of Agriculture, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, China
| | - Senmiao Fan
- State Key Laboratory of Cotton Biology, Key Laboratory of Biological and Genetic Breeding of Cotton, The Ministry of Agriculture, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, China
| | - Xiao Jiang
- State Key Laboratory of Cotton Biology, Key Laboratory of Biological and Genetic Breeding of Cotton, The Ministry of Agriculture, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, China
| | - Yulong Feng
- Zhengzhou Research Base, State Key Laboratory of Cotton Biology, Zhengzhou University, Zhengzhou, China
| | - Lipeng Zhang
- State Key Laboratory of Cotton Biology, Key Laboratory of Biological and Genetic Breeding of Cotton, The Ministry of Agriculture, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, China
| | - Doudou Niu
- State Key Laboratory of Cotton Biology, Key Laboratory of Biological and Genetic Breeding of Cotton, The Ministry of Agriculture, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, China
| | - Shen Huang
- Zhengzhou University of Light Industry College of Food and Bioengineering, Zhengzhou, China
| | - Wankui Gong
- State Key Laboratory of Cotton Biology, Key Laboratory of Biological and Genetic Breeding of Cotton, The Ministry of Agriculture, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, China
| | - Youlu Yuan
- State Key Laboratory of Cotton Biology, Key Laboratory of Biological and Genetic Breeding of Cotton, The Ministry of Agriculture, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, China.,Zhengzhou Research Base, State Key Laboratory of Cotton Biology, Zhengzhou University, Zhengzhou, China
| | - Haihong Shang
- State Key Laboratory of Cotton Biology, Key Laboratory of Biological and Genetic Breeding of Cotton, The Ministry of Agriculture, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, China.,Zhengzhou Research Base, State Key Laboratory of Cotton Biology, Zhengzhou University, Zhengzhou, China
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Blanco P, Corona F, Martinez JL. Mechanisms and phenotypic consequences of acquisition of tigecycline resistance by Stenotrophomonas maltophilia. J Antimicrob Chemother 2020; 74:3221-3230. [PMID: 31369109 DOI: 10.1093/jac/dkz326] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 06/17/2019] [Accepted: 07/02/2019] [Indexed: 01/05/2023] Open
Abstract
OBJECTIVES To elucidate the potential mutation-driven mechanisms involved in the acquisition of tigecycline resistance by the opportunistic pathogen Stenotrophomonas maltophilia. The mutational trajectories and their effects on bacterial fitness, as well as cross-resistance and/or collateral susceptibility to other antibiotics, were also addressed. METHODS S. maltophilia populations were submitted to experimental evolution in the presence of increasing concentrations of tigecycline for 30 days. The genetic mechanisms involved in the acquisition of tigecycline resistance were determined by WGS. Resistance was evaluated by performing MIC assays. Fitness of the evolved populations and individual clones was assessed by measurement of the maximum growth rates. RESULTS All the tigecycline-evolved populations attained high-level resistance to tigecycline following different mutational trajectories, yet with some common elements. Among the mechanisms involved in low susceptibility to tigecycline, mutations in the SmeDEF efflux pump negative regulator smeT, changes in proteins involved in the biogenesis of the ribosome and modifications in the LPS biosynthesis pathway seem to play a major role. Besides tigecycline resistance, the evolved populations presented cross-resistance to other antibiotics, such as aztreonam and quinolones, and they were hypersusceptible to fosfomycin, suggesting a possible combination treatment. Further, we found that the selected resistance mechanisms impose a relevant fitness cost when bacteria grow in the absence of antibiotic. CONCLUSIONS Mutational resistance to tigecycline was easily selected during exposure to this antibiotic. However, the fitness cost may compromise the maintenance of S. maltophilia tigecycline-resistant populations in the absence of antibiotic.
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Affiliation(s)
- Paula Blanco
- Centro Nacional de Biotecnología, CSIC, Madrid, Spain
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8
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Catalytic mechanism of UDP-glucose dehydrogenase. Biochem Soc Trans 2019; 47:945-955. [PMID: 31189734 DOI: 10.1042/bst20190257] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 05/15/2019] [Accepted: 05/21/2019] [Indexed: 11/17/2022]
Abstract
UDP-glucose dehydrogenase (UGDH), an oxidoreductase, catalyzes the NAD+-dependent four-electron oxidation of UDP-glucose to UDP-glucuronic acid. The catalytic mechanism of UGDH remains controversial despite extensive investigation and is classified into two types according to whether an aldehyde intermediate is generated in the first oxidation step. The first type, which involves the presence of this putative aldehyde, is inconsistent with some experimental findings. In contrast, the second type, which indicates that the first oxidation step bypasses the aldehyde via an NAD+-dependent bimolecular nucleophilic substitution (SN2) reaction, is consistent with the experimental phenomena, including those that cannot be explained by the first type. This NAD+-dependent SN2 mechanism is thus more reasonable and likely applicable to other oxidoreductases that catalyze four-electron oxidation reactions.
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Reamtong O, Rujimongkon K, Sookrung N, Saeung A, Thiangtrongjit T, Sakolvaree Y, Thammapalo S, Loymek S, Chaicumpa W. Immunome and immune complex-forming components of Brugia malayi identified by microfilaremic human sera. Exp Parasitol 2019; 200:92-98. [PMID: 30991039 DOI: 10.1016/j.exppara.2019.04.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 03/27/2019] [Accepted: 04/12/2019] [Indexed: 11/25/2022]
Abstract
Adult Brugia malayi proteins with high potential as epidemiological markers, diagnostic and therapeutic targets, and/or vaccine candidates were revealed by using microfilaremic human sera and an immunoproteomic approach. They were HSP70, cytoplasmic intermediate filament protein, independent phosphoglycerate mutase, and enolase. Brugia malayi microfilaria-specific proteins that formed circulating immune complexes (ICs) were investigated. The IC-forming proteins were orthologues of hypothetical protein Bm1_12480, Pao retrotransposon peptidase family protein, uncoordinated protein 44, NAD-binding domain containing protein of the UDP-glucose/GDP-mannose dehydrogenase family which contained ankyrin repeat region, ZU5 domain with C-terminal death domain, C2 domain containing protein, and FLJ90013 protein of the eukaryotic membrane protein family. Antibodies to these proteins were not free in the microfilaremic sera, raising the possible role of the IC-forming proteins in an immune evasion mechanism of the circulating microfilariae to avoid antibody-mediated-host immunity. Moreover, detection of these ICs should be able to replace the inconvenient night blood sampling for microfilaria in an evaluation of efficacy of anti-microfilarial agents.
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Affiliation(s)
- Onrapak Reamtong
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand
| | - Kitiya Rujimongkon
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand
| | - Nitat Sookrung
- Biomedical Research Incubation Unit, Department of Research, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, 10700, Thailand; Center of Research Excellence on Therapeutic Proteins and Antibody Engineering, Department of Parasitology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, 10700, Thailand
| | - Atiporn Saeung
- Department of Parasitology, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand
| | - Tipparat Thiangtrongjit
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand
| | - Yuwaporn Sakolvaree
- Center of Research Excellence on Therapeutic Proteins and Antibody Engineering, Department of Parasitology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, 10700, Thailand
| | - Suwich Thammapalo
- The Office of Disease Prevention and Control 12, Songkhla, 90000, Thailand
| | - Sumat Loymek
- The Office of Disease Prevention and Control 12, Songkhla, 90000, Thailand
| | - Wanpen Chaicumpa
- Center of Research Excellence on Therapeutic Proteins and Antibody Engineering, Department of Parasitology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, 10700, Thailand.
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10
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Kang Y, Li P, Zeng X, Chen X, Xie Y, Zeng Y, Zhang Y, Xie T. Biosynthesis, structure and antioxidant activities of xanthan gum from Xanthomonas campestris with additional furfural. Carbohydr Polym 2019; 216:369-375. [PMID: 31047079 DOI: 10.1016/j.carbpol.2019.04.018] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Revised: 03/15/2019] [Accepted: 04/03/2019] [Indexed: 01/11/2023]
Abstract
Lignocellulosic-like materials are potentially low-cost fermentation substrates, but their pretreatment brings about by-products. This work investigated the effects of furfural on xanthan gum (XG) production, and product quality was evaluated by structure, viscosity and antioxidant capacities. Xanthomonas campestris maintained steady polysaccharide yield (above 13 g·L-1) with enhanced cell growth at low furfural concentrations (below 3.2 g·L-1). The products were verified as XG by FT-IR, XRD, NMR and monosaccharide analysis. Moreover, they were found to have reduced acetyl, rising pyruvate and up-to-down glucuronic acid groups as increasing furfural concentration. Furthermore, XG product with 1 g·L-1 furfural addition showed the best hydroxyl scavenging effects, though reducing powers presented no variation. It was demonstrated that furfural, the common hydrolysis by-product, was not necessarily an inhibitor for fermentation, and an appropriate amount of furfural was beneficial to XG production with steady yield and good quality.
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Affiliation(s)
- Yan Kang
- Department of Pharmaceutical & Biological Engineering, School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China.
| | - Panyu Li
- Department of Pharmaceutical & Biological Engineering, School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China.
| | - Xiaotong Zeng
- Department of Pharmaceutical & Biological Engineering, School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China.
| | - Xi Chen
- Department of Pharmaceutical & Biological Engineering, School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China.
| | - Yi Xie
- Department of Pharmaceutical & Biological Engineering, School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China.
| | - Yu Zeng
- Department of Pharmaceutical & Biological Engineering, School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China.
| | - Yongkui Zhang
- Department of Pharmaceutical & Biological Engineering, School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China.
| | - Tonghui Xie
- Department of Pharmaceutical & Biological Engineering, School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China.
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Chen J, Yu Y, Gao J, Yang S. UDP-glucose Dehydrogenase: The First-step Oxidation Is an NAD +-dependent Bimolecular Nucleophilic Substitution Reaction (S N2). Int J Biol Sci 2019; 15:341-350. [PMID: 30745825 PMCID: PMC6367545 DOI: 10.7150/ijbs.28904] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 11/11/2018] [Indexed: 11/05/2022] Open
Abstract
UDP-glucose dehydrogenase (UGDH) catalyzes the conversion of UDP-glucose to UDP-glucuronic acid by NAD+-dependent two-fold oxidation. Despite extensive investigation into the catalytic mechanism of UGDH, the previously proposed mechanisms regarding the first-step oxidation are somewhat controversial and inconsistent with some biochemical evidence, which instead supports a mechanism involving an NAD+-dependent bimolecular nucleophilic substitution (SN2) reaction. To verify this speculation, the essential Cys residue of Streptococcus zooepidemicus UGDH (SzUGDH) was changed to an Ala residue, and the resulting Cys260Ala mutant and SzUGDH were then co-expressed in vivo via a single-crossover homologous recombination method. Contrary to the previously proposed mechanisms, which predict the formation of the capsular polysaccharide hyaluronan, the resulting strain instead produced an amide derivative of hyaluronan, as validated via proteinase K digestion, ninhydrin reaction, FT-IR and NMR. This result is compatible with the NAD+-dependent SN2 mechanism.
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Affiliation(s)
- Jun Chen
- School of Environmental & Biological Engineering, Nanjing University of Science and Technology, Xiaolingwei 200, Nanjing, China, 210094
| | - Yang Yu
- School of Environmental & Biological Engineering, Nanjing University of Science and Technology, Xiaolingwei 200, Nanjing, China, 210094
| | - Jiaojiao Gao
- School of Environmental & Biological Engineering, Nanjing University of Science and Technology, Xiaolingwei 200, Nanjing, China, 210094
| | - Shulin Yang
- School of Environmental & Biological Engineering, Nanjing University of Science and Technology, Xiaolingwei 200, Nanjing, China, 210094
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12
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Potential biological process of X-linked inhibitor of apoptosis protein in renal cell carcinoma based upon differential protein expression analysis. Oncol Lett 2017; 15:821-832. [PMID: 29403558 PMCID: PMC5780803 DOI: 10.3892/ol.2017.7383] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 09/28/2017] [Indexed: 01/04/2023] Open
Abstract
The X-linked inhibitor of apoptosis protein (XIAP) is the best characterized member of the IAP family and is a potent inhibitor of the caspase/apoptosis pathway. It has also been revealed that XIAP has additional biological functions that rely on its direct inhibition of apoptosis. In the present study, stably transfected Caki-1 cells with XIAP-knockdown were generated, and an isobaric tag for relative and absolute quantitation-based proteomics approach was employed to investigate the regulatory mechanism of XIAP in renal cell carcinoma (RCC). The results demonstrate that the sensitivity of the RCC cell line to apoptotic stimulation increased markedly with XIAP-knockdown. A number of differentially expressed proteins were detected between the original Caki-1 cell line and the XIAP-knockdown Caki-1 cell line; 87 at 0 h (prior to etoposide treatment), 178 at 0.5 h and 169 at 3 h, while no differentially expressed proteins were detected (ratio >1.5 or <0.5; P<0.05) at 12 h after etoposide treatment. Through analysis of the differentially expressed proteins, it was revealed that XIAP may participate in the tumor protein p53 pathway, the Wnt signaling pathway, glucose metabolism, endoplasmic reticulum stress, cytoskeletal regulation and DNA repair. These results indicate that XIAP may have a number of biological functions and may provide an insight into the biomedical significance of XIAP overexpression in RCC.
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Grady G, Thelen A, Albers J, Ju T, Guo J, Barycki JJ, Simpson MA. Inhibiting Hexamer Disassembly of Human UDP-Glucose Dehydrogenase by Photoactivated Amino Acid Cross-Linking. Biochemistry 2016; 55:3157-64. [PMID: 27198584 DOI: 10.1021/acs.biochem.6b00259] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The enzyme UDP-glucose dehydrogenase (UGDH) catalyzes the reaction of UDP-glucose to UDP-glucuronate through two successive NAD(+)-dependent oxidation steps. Human UGDH apoprotein is purified as a mixture of dimeric and hexameric species. Addition of substrate and cofactor stabilizes the oligomeric state to primarily the hexameric form. To determine if the dynamic conformations of hUGDH are required for catalytic activity, we used site-specific unnatural amino acid incorporation to facilitate cross-linking of monomeric subunits into predominantly obligate oligomeric species. Optimal cross-linking was achieved by encoding p-benzoyl-l-phenylalanine at position 458, normally a glutamine located within the dimer-dimer interface, and exposing the enzyme to long wavelength ultraviolet (UV) radiation in the presence of substrate and cofactor. Hexameric complexes were purified by gel filtration chromatography and found to contain significant fractions of dimer and trimer (approximately 50%) along with another 10% higher-molecular mass species. The activity of the cross-linked enzyme was reduced by almost 60% relative to that of the un-cross-linked UGDH mutant, and UV exposure had no effect on the activity of the wild-type enzyme. These results support a model for catalysis in which the ability to dissociate the dimer-dimer interface is as important for maximal enzyme function as has been previously shown for the formation of the hexamer.
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Affiliation(s)
- George Grady
- Department of Biochemistry, University of Nebraska , Lincoln, Nebraska 68588-0664, United States
| | - Ashley Thelen
- Department of Biochemistry, University of Nebraska , Lincoln, Nebraska 68588-0664, United States
| | - Jaleen Albers
- Department of Biochemistry, University of Nebraska , Lincoln, Nebraska 68588-0664, United States
| | - Tong Ju
- Department of Chemistry, University of Nebraska , Lincoln, Nebraska 68588-0304, United States
| | - Jiantao Guo
- Department of Chemistry, University of Nebraska , Lincoln, Nebraska 68588-0304, United States
| | - Joseph J Barycki
- Department of Biochemistry, University of Nebraska , Lincoln, Nebraska 68588-0664, United States
| | - Melanie A Simpson
- Department of Biochemistry, University of Nebraska , Lincoln, Nebraska 68588-0664, United States
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14
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Chu X, Han J, Guo D, Fu Z, Liu W, Tao Y. Characterization of UDP-glucose dehydrogenase from Pasteurella multocida CVCC 408 and its application in hyaluronic acid biosynthesis. Enzyme Microb Technol 2016; 85:64-70. [DOI: 10.1016/j.enzmictec.2015.12.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Revised: 12/17/2015] [Accepted: 12/18/2015] [Indexed: 10/22/2022]
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15
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Duan XC, Lu AM, Gu B, Cai ZP, Ma HY, Wei S, Laborda P, Liu L, Voglmeir J. Functional characterization of the UDP-xylose biosynthesis pathway in Rhodothermus marinus. Appl Microbiol Biotechnol 2015; 99:9463-72. [PMID: 26033773 DOI: 10.1007/s00253-015-6683-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Revised: 04/20/2015] [Accepted: 05/07/2015] [Indexed: 10/23/2022]
Abstract
UDP-glucuronic acid dehydrogenase (UGD) and UDP-xylose synthase (UXS) are the two enzymes responsible for the biosynthesis of UDP-xylose from UDP-glucose. Several UGDs from bacterial sources, which oxidize UDP-glucose to glucuronic acid, have been found and functionally characterized whereas only few reports on bacterial UXS isoforms exist. Rhodothermus marinus, a halothermophilic bacterium commonly found in hot springs, proved to be a valuable source of carbohydrate active enzymes of biotechnological interest, such as xylanases, mannanases, and epimerases. However, no enzymes of R. marinus involved in the biosynthesis or modification of nucleotide sugars have been reported yet. Herein, we describe the cloning and characterization of two putative UGD (RmUGD1 and RmUGD2) and one UXS (RmUXS) isoform from this organism. All three enzymes could be expressed in recombinant form and purified to near homogeneity. UPLC- and NMR-based activity tests showed that RmUGD1 and RmUXS are indeed active enzymes, whereas no enzymatic activity could be detected by RmUGD2. Both RmUGD1 and RmUXS showed a temperature optimum of 60 °C, with almost no loss of activity after 1 h exposure at 70 °C. No metal ions were required for enzymatic activities. Zn(2+) ions strongly inhibited both enzymes. RmUGD1 showed higher salt tolerance and had a higher pH optimum than RmUXS. Furthermore, RmUGD1 was inhibited by UDP-xylose at higher concentrations. By coupling recombinant RmUXS and RmUGD1, UDP-xylose could be successfully synthesized directly from UDP-glucose. The high activity of the herein described enzymes make RmUGD1 and RmUXS the first thermo-tolerant biocatalysts for the synthesis of UDP-glucuronic acid and UDP-xylose.
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Affiliation(s)
- Xu C Duan
- Glycomics and Glycan Bioengineering Research Center (GGBRC), College of Food Science and Technology, Nanjing Agricultural University, Nanjing, People's Republic of China
| | - Ai M Lu
- College of Sciences, Nanjing Agricultural University, Nanjing, People's Republic of China
| | - Bin Gu
- Glycomics and Glycan Bioengineering Research Center (GGBRC), College of Food Science and Technology, Nanjing Agricultural University, Nanjing, People's Republic of China
| | - Zhi P Cai
- Glycomics and Glycan Bioengineering Research Center (GGBRC), College of Food Science and Technology, Nanjing Agricultural University, Nanjing, People's Republic of China
| | - Hong Y Ma
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, People's Republic of China
| | - Shuang Wei
- Glycomics and Glycan Bioengineering Research Center (GGBRC), College of Food Science and Technology, Nanjing Agricultural University, Nanjing, People's Republic of China
| | - Pedro Laborda
- Glycomics and Glycan Bioengineering Research Center (GGBRC), College of Food Science and Technology, Nanjing Agricultural University, Nanjing, People's Republic of China
| | - Li Liu
- Glycomics and Glycan Bioengineering Research Center (GGBRC), College of Food Science and Technology, Nanjing Agricultural University, Nanjing, People's Republic of China.
| | - Josef Voglmeir
- Glycomics and Glycan Bioengineering Research Center (GGBRC), College of Food Science and Technology, Nanjing Agricultural University, Nanjing, People's Republic of China.
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16
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Du Q, Tian J, Yang X, Pan W, Xu B, Li B, Ingvarsson PK, Zhang D. Identification of additive, dominant, and epistatic variation conferred by key genes in cellulose biosynthesis pathway in Populus tomentosa†. DNA Res 2015; 22:53-67. [PMID: 25428896 PMCID: PMC4379978 DOI: 10.1093/dnares/dsu040] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Accepted: 10/22/2014] [Indexed: 12/29/2022] Open
Abstract
Economically important traits in many species generally show polygenic, quantitative inheritance. The components of genetic variation (additive, dominant and epistatic effects) of these traits conferred by multiple genes in shared biological pathways remain to be defined. Here, we investigated 11 full-length genes in cellulose biosynthesis, on 10 growth and wood-property traits, within a population of 460 unrelated Populus tomentosa individuals, via multi-gene association. To validate positive associations, we conducted single-marker analysis in a linkage population of 1,200 individuals. We identified 118, 121, and 43 associations (P< 0.01) corresponding to additive, dominant, and epistatic effects, respectively, with low to moderate proportions of phenotypic variance (R(2)). Epistatic interaction models uncovered a combination of three non-synonymous sites from three unique genes, representing a significant epistasis for diameter at breast height and stem volume. Single-marker analysis validated 61 associations (false discovery rate, Q ≤ 0.10), representing 38 SNPs from nine genes, and its average effect (R(2) = 3.8%) nearly 2-fold higher than that identified with multi-gene association, suggesting that multi-gene association can capture smaller individual variants. Moreover, a structural gene-gene network based on tissue-specific transcript abundances provides a better understanding of the multi-gene pathway affecting tree growth and lignocellulose biosynthesis. Our study highlights the importance of pathway-based multiple gene associations to uncover the nature of genetic variance for quantitative traits and may drive novel progress in molecular breeding.
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Affiliation(s)
- Qingzhang Du
- National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, P. R. China Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, P. R. China
| | - Jiaxing Tian
- National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, P. R. China Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, P. R. China
| | - Xiaohui Yang
- National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, P. R. China Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, P. R. China
| | - Wei Pan
- National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, P. R. China Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, P. R. China
| | - Baohua Xu
- National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, P. R. China Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, P. R. China
| | - Bailian Li
- National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, P. R. China Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, P. R. China Department of Forestry, North Carolina State University, Raleigh, NC 27695-8203, USA
| | - Pär K Ingvarsson
- Department of Ecology and Environmental Science, Umeå Plant Science Centre, Umeå University, Umeå SE-901 87, Sweden
| | - Deqiang Zhang
- National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, P. R. China Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, P. R. China
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17
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Improvement of LysM-mediated surface display of designed ankyrin repeat proteins (DARPins) in recombinant and nonrecombinant strains of Lactococcus lactis and Lactobacillus Species. Appl Environ Microbiol 2015; 81:2098-106. [PMID: 25576617 DOI: 10.1128/aem.03694-14] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Safety and probiotic properties make lactic acid bacteria (LAB) attractive hosts for surface display of heterologous proteins. Protein display on nonrecombinant microorganisms is preferred for therapeutic and food applications due to regulatory requirements. We displayed two designed ankyrin repeat proteins (DARPins), each possessing affinity for the Fc region of human IgG, on the surface of Lactococcus lactis by fusing them to the Usp45 secretion signal and to the peptidoglycan-binding C terminus of AcmA, containing lysine motif (LysM) repeats. Growth medium containing a secreted fusion protein was used to test its heterologous binding to 10 strains of species of the genus Lactobacillus, using flow cytometry, whole-cell enzyme-linked immunosorbent assay (ELISA), and fluorescence microscopy. The fusion proteins bound to the surfaces of all lactobacilli; however, binding to the majority of bacteria was only 2- to 5-fold stronger than that of the control. Lactobacillus salivarius ATCC 11741 demonstrated exceptionally strong binding (32- to 55-fold higher than that of the control) and may therefore be an attractive host for nonrecombinant surface display. Genomic comparison of the species indicated the exopolysaccharides of Lb. salivarius as a possible reason for the difference. Additionally, a 15-fold concentration-dependent increase in nonrecombinant surface display on L. lactis was demonstrated by growing bacteria with sublethal concentrations of the antibiotics chloramphenicol and erythromycin. Nonrecombinant surface display on LAB, based on LysM repeats, was optimized by selecting Lactobacillus salivarius ATCC 11741 as the optimal host and by introducing antibiotics as additives for increasing surface display on L. lactis. Additionally, effective display of DARPins on the surfaces of nonrecombinant LAB has opened up several new therapeutic possibilities.
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18
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Superina S, Borovina A, Ciruna B. Analysis of maternal-zygotic ugdh mutants reveals divergent roles for HSPGs in vertebrate embryogenesis and provides new insight into the initiation of left-right asymmetry. Dev Biol 2014; 387:154-66. [PMID: 24462977 DOI: 10.1016/j.ydbio.2014.01.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 11/20/2013] [Accepted: 01/14/2014] [Indexed: 11/25/2022]
Abstract
Growth factors and morphogens regulate embryonic patterning, cell fate specification, cell migration, and morphogenesis. The activity and behavior of these signaling molecules are regulated in the extracellular space through interactions with proteoglycans (Bernfield et al., 1999; Perrimon and Bernfield 2000; Lander and Selleck 2000; Selleck 2000). Proteoglycans are high molecular-weight proteins consisting of a core protein with covalently linked glycosaminoglycan (GAG) side chains, which are thought to mediate ligand interaction. Drosophila mutant embryos deficient for UDP-glucose dehydrogenase activity (Ugdh, required for GAG synthesis) exhibit abnormal Fgf, Wnt and TGFß signaling and die during gastrulation, indicating a broad and critical role for proteoglycans during early embryonic development (Lin et al., 1999; Lin and Perrimon 2000) (Hacker et al., 1997). Mouse Ugdh mutants also die at gastrulation, however, only Fgf signaling appears disrupted (Garcia-Garcia and Anderson, 2003). These findings suggested a possible divergence in the requirement for proteoglycans during Drosophila and mouse embryogenesis, and that mammals may have evolved alternative means of regulating Wnt and TGFß activity. To further examine the function of proteoglycans in vertebrate development, we have characterized zebrafish mutants devoid of both maternal and zygotic Ugdh/Jekyll activity (MZjekyll). We demonstrate that MZjekyll mutant embryos display abnormal Fgf, Shh, and Wnt signaling activities, with concomitant defects in central nervous system patterning, cardiac ventricular fate specification and axial morphogenesis. Furthermore, we uncover a novel role for proteoglycans in left-right pattern formation. Our findings resolve longstanding questions into the evolutionary conservation of Ugdh function and provide new mechanistic insights into the initiation of left-right asymmetry.
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Affiliation(s)
- Simone Superina
- Program in Developmental & Stem Cell Biology, The Hospital for Sick Children, Toronto, Ont., Canada M5G 1X8; Department of Molecular Genetics, The University of Toronto, Toronto, Ont., Canada M5S 1A8
| | - Antonia Borovina
- Program in Developmental & Stem Cell Biology, The Hospital for Sick Children, Toronto, Ont., Canada M5G 1X8; Department of Molecular Genetics, The University of Toronto, Toronto, Ont., Canada M5S 1A8
| | - Brian Ciruna
- Program in Developmental & Stem Cell Biology, The Hospital for Sick Children, Toronto, Ont., Canada M5G 1X8; Department of Molecular Genetics, The University of Toronto, Toronto, Ont., Canada M5S 1A8.
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19
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Hyde AS, Thelen AM, Barycki JJ, Simpson MA. UDP-glucose dehydrogenase activity and optimal downstream cellular function require dynamic reorganization at the dimer-dimer subunit interfaces. J Biol Chem 2013; 288:35049-57. [PMID: 24145036 DOI: 10.1074/jbc.m113.519090] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
UDP-glucose dehydrogenase (UGDH) provides precursors for steroid elimination, hyaluronan production, and glycosaminoglycan synthesis. The wild-type UGDH enzyme purifies in a hexamer-dimer equilibrium and transiently undergoes dynamic motion that exposes the dimer-dimer interface during catalysis. In the current study we created and characterized point mutations that yielded exclusively dimeric species (obligate dimer, T325D), dimeric species that could be induced to form hexamers in the ternary complex with substrate and cofactor (T325A), and a previously described exclusively hexameric species (UGDHΔ132) to investigate the role of quaternary structure in regulation of the enzyme. Characterization of the purified enzymes revealed a significant decrease in the enzymatic activity of the obligate dimer and hexamer mutants. Kinetic analysis of wild-type UGDH and the inducible hexamer, T325A, showed that upon increasing enzyme concentration, which favors the hexameric species, activity was modestly decreased and exhibited cooperativity. In contrast, cooperative kinetic behavior was not observed in the obligate dimer, T325D. These observations suggest that the regulation of the quaternary assembly of the enzyme is essential for optimal activity and allosteric regulation. Comparison of kinetic and thermal stability parameters revealed structurally dependent properties consistent with a role for controlled assembly and disassembly of the hexamer in the regulation of UGDH. Finally, both T325A and T325D mutants were significantly less efficient in promoting downstream hyaluronan production by HEK293 cells. These data support a model that requires an operational dimer-hexamer equilibrium to function efficiently and preserve regulated activity in the cell.
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Affiliation(s)
- Annastasia S Hyde
- From the Department of Biochemistry, University of Nebraska, Lincoln, Nebraska 68588-0664
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20
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Mainprize IL, Bean JD, Bouwman C, Kimber MS, Whitfield C. The UDP-glucose dehydrogenase of Escherichia coli K-12 displays substrate inhibition by NAD that is relieved by nucleotide triphosphates. J Biol Chem 2013; 288:23064-74. [PMID: 23792965 DOI: 10.1074/jbc.m113.486613] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
UDP-glucose dehydrogenase (Ugd) generates UDP-glucuronic acid, an important precursor for the production of many hexuronic acid-containing bacterial surface glycostructures. In Escherichia coli K-12, Ugd is important for biosynthesis of the environmentally regulated exopolysaccharide known as colanic acid, whereas in other E. coli isolates, the same enzyme is required for production of the constitutive group 1 capsular polysaccharides, which act as virulence determinants. Recent studies have implicated tyrosine phosphorylation in the activation of Ugd from E. coli K-12, although it is not known if this is a feature shared by bacterial Ugd proteins. The activities of Ugd from E. coli K-12 and from the group 1 capsule prototype (serotype K30) were compared. Surprisingly, for both enzymes, site-directed Tyr → Phe mutants affecting the previously proposed phosphorylation site retained similar kinetic properties to the wild-type protein. Purified Ugd from E. coli K-12 had significant levels of NAD substrate inhibition, which could be alleviated by the addition of ATP and several other nucleotide triphosphates. Mutations in a previously identified UDP-glucuronic acid allosteric binding site decreased the binding affinity of the nucleotide triphosphate. Ugd from E. coli serotype K30 was not inhibited by NAD, but its activity still increased in the presence of ATP.
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Affiliation(s)
- Iain L Mainprize
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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21
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Kadirvelraj R, Sennett NC, Custer GS, Phillips RS, Wood ZA. Hysteresis and negative cooperativity in human UDP-glucose dehydrogenase. Biochemistry 2013; 52:1456-65. [PMID: 23363239 DOI: 10.1021/bi301593c] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Human UDP-α-d-glucose 6-dehydrogenase (hUGDH) forms a hexamer that catalyzes the NAD(+)-dependent oxidation of UDP-α-d-glucose (UDG) to produce UDP-α-d-glucuronic acid. Mammalian UGDH displays hysteresis (observed as a lag in progress curves), indicating that the enzyme undergoes a slow transition from an inactive to an active state. Here we show that hUGDH is sensitive to product inhibition during the lag. The inhibition results in a systematic decrease in steady-state velocity and makes the lag appear to have a second-order dependence on enzyme concentration. Using transient-state kinetics, we confirm that the lag is in fact due to a substrate and cofactor-induced isomerization of the enzyme. We also show that the cofactor binds to the hUGDH:UDG complex with negative cooperativity. This suggests that the isomerization may be related to the formation of an asymmetric enzyme complex. We propose that the hysteresis in hUGDH is the consequence of a functional adaptation; by slowing the response of hUGDH to sudden increases in the flux of UDG, the other biochemical pathways that use this important metabolite (i.e., glycolysis) will have a competitive edge.
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Affiliation(s)
- Renuka Kadirvelraj
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602, United States
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22
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Sennett NC, Kadirvelraj R, Wood ZA. Cofactor binding triggers a molecular switch to allosterically activate human UDP-α-D-glucose 6-dehydrogenase. Biochemistry 2012; 51:9364-74. [PMID: 23106432 DOI: 10.1021/bi301067w] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Human UDP-α-D-glucose dehydrogenase (hUGDH) catalyzes the NAD(+)-dependent oxidation of UDP-α-D-glucose (UDG) to produce UDP-α-D-glucuronic acid. The oligomeric structure of hUGDH is dynamic and can form two distinct hexameric complexes in solution. The active form of hUGDH consists of dimers that undergo a concentration-dependent association to form a hexamer with 32 symmetry. In the presence of the allosteric feedback inhibitor UDP-α-D-xylose (UDX), hUGDH changes shape to form an inactive, horseshoe-shaped complex. Previous studies have identified the UDX-induced allosteric mechanism that changes the hexameric structure to inhibit the enzyme. Here, we investigate the role of the 32 symmetry hexamer in the catalytic cycle. We engineered a stable hUGDH dimer by introducing a charge-switch substitution (K94E) in the hexamer-building interface (hUGDH(K94E)). The k(cat) of hUGDH(K94E) is ~160-fold lower than that of the wild-type enzyme, suggesting that the hexamer is the catalytically relevant state. We also show that cofactor binding triggers the formation of the 32 symmetry hexamer, but UDG is needed for the stability of the complex. The hUGDH(K94E) crystal structure at 2.08 Å resolution identifies loop(88-110) as the cofactor-responsive allosteric switch that drives hexamer formation; loop(88-110) directly links cofactor binding to the stability of the hexamer-building interface. In the interface, loop(88-110) packs against the Thr131-loop/α6 helix, the allosteric switch that responds to the feedback inhibitor UDX. We also identify a structural element (the S-loop) that explains the indirect stabilization of the hexamer by substrate and supports a sequential, ordered binding of the substrate and cofactor. These observations support a model in which (i) UDG binds to the dimer and stabilizes the S-loop to promote cofactor binding and (ii) cofactor binding orders loop(88-110) to induce formation of the catalytically active hexamer.
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Affiliation(s)
- Nicholas C Sennett
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602, United States
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Sakuraba H, Kawai T, Yoneda K, Ohshima T. Structure of a UDP-glucose dehydrogenase from the hyperthermophilic archaeon Pyrobaculum islandicum. Acta Crystallogr Sect F Struct Biol Cryst Commun 2012; 68:1003-7. [PMID: 22949183 PMCID: PMC3433186 DOI: 10.1107/s1744309112030667] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Accepted: 07/04/2012] [Indexed: 06/01/2023]
Abstract
The crystal structure of an extremely thermostable UDP-glucose dehydrogenase (UDP-GDH) from the hyperthermophilic archaeon Pyrobaculum islandicum was determined at a resolution of 2.0 Å. The overall fold was comprised of an N-terminal NAD(+) dinucleotide binding domain and a C-terminal UDP-sugar binding domain connected by a long α-helix, and the main-chain coordinates of the enzyme were similar to those of previously studied UDP-GDHs, including the enzymes from Burkholderia cepacia, Streptococcus pyogenes and Klebsiella pneumoniae. However, the sizes of several surface loops in P. islandicum UDP-GDH were much smaller than the corresponding loops in B. cepacia UDP-GDH but were comparable to those of the S. pyogenes and K. pneumoniae enzymes. Structural comparison revealed that the presence of extensive intersubunit hydrophobic interactions, as well as the formation of an intersubunit aromatic pair network, is likely to be the main factor contributing to the hyperthermostability of P. islandicum UDP-GDH.
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Affiliation(s)
- Haruhiko Sakuraba
- Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, 2393 Ikenobe, Miki-cho, Kita-gun, Kagawa 761-0795, Japan
| | - Tomoyuki Kawai
- Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, 2393 Ikenobe, Miki-cho, Kita-gun, Kagawa 761-0795, Japan
| | - Kazunari Yoneda
- Department of Bioscience, School of Agriculture, Tokai University, Aso, Kumamoto 869-1404, Japan
| | - Toshihisa Ohshima
- Microbial Genetics Division, Institute of Genetic Resources, Faculty of Agriculture, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan
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25
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Hyde AS, Farmer EL, Easley KE, van Lammeren K, Christoffels VM, Barycki JJ, Bakkers J, Simpson MA. UDP-glucose dehydrogenase polymorphisms from patients with congenital heart valve defects disrupt enzyme stability and quaternary assembly. J Biol Chem 2012; 287:32708-16. [PMID: 22815472 DOI: 10.1074/jbc.m112.395202] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Cardiac valve defects are a common congenital heart malformation and a significant clinical problem. Defining molecular factors in cardiac valve development has facilitated identification of underlying causes of valve malformation. Gene disruption in zebrafish revealed a critical role for UDP-glucose dehydrogenase (UGDH) in valve development, so this gene was screened for polymorphisms in a patient population suffering from cardiac valve defects. Two genetic substitutions were identified and predicted to encode missense mutations of arginine 141 to cysteine and glutamate 416 to aspartate, respectively. Using a zebrafish model of defective heart valve formation caused by morpholino oligonucleotide knockdown of UGDH, transcripts encoding the UGDH R141C or E416D mutant enzymes were unable to restore cardiac valve formation and could only partially rescue cardiac edema. Characterization of the mutant recombinant enzymes purified from Escherichia coli revealed modest alterations in the enzymatic activity of the mutants and a significant reduction in the half-life of enzyme activity at 37 °C. This reduction in activity could be propagated to the wild-type enzyme in a 1:1 mixed reaction. Furthermore, the quaternary structure of both mutants, normally hexameric, was destabilized to favor the dimeric species, and the intrinsic thermal stability of the R141C mutant was highly compromised. The results are consistent with the reduced function of both missense mutations significantly reducing the ability of UGDH to provide precursors for cardiac cushion formation, which is essential to subsequent valve formation. The identification of these polymorphisms in patient populations will help identify families genetically at risk for valve defects.
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Affiliation(s)
- Annastasia S Hyde
- Department of Biochemistry, University of Nebraska, Lincoln, Nebraska 68588-0664, USA
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26
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Egger S, Chaikuad A, Klimacek M, Kavanagh KL, Oppermann U, Nidetzky B. Structural and kinetic evidence that catalytic reaction of human UDP-glucose 6-dehydrogenase involves covalent thiohemiacetal and thioester enzyme intermediates. J Biol Chem 2011; 287:2119-29. [PMID: 22123821 PMCID: PMC3265891 DOI: 10.1074/jbc.m111.313015] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Biosynthesis of UDP-glucuronic acid by UDP-glucose 6-dehydrogenase (UGDH) occurs through the four-electron oxidation of the UDP-glucose C6 primary alcohol in two NAD+-dependent steps. The catalytic reaction of UGDH is thought to involve a Cys nucleophile that promotes formation of a thiohemiacetal enzyme intermediate in the course of the first oxidation step. The thiohemiacetal undergoes further oxidation into a thioester, and hydrolysis of the thioester completes the catalytic cycle. Herein we present crystallographic and kinetic evidence for the human form of UGDH that clarifies participation of covalent catalysis in the enzymatic mechanism. Substitution of the putative catalytic base for water attack on the thioester (Glu161) by an incompetent analog (Gln161) gave a UGDH variant (E161Q) in which the hydrolysis step had become completely rate-limiting so that a thioester enzyme intermediate accumulated at steady state. By crystallizing E161Q in the presence of 5 mm UDP-glucose and 2 mm NAD+, we succeeded in trapping a thiohemiacetal enzyme intermediate and determined its structure at 2.3 Å resolution. Cys276 was covalently modified in the structure, establishing its role as catalytic nucleophile of the reaction. The thiohemiacetal reactive C6 was in a position suitable to become further oxidized by hydride transfer to NAD+. The proposed catalytic mechanism of human UGDH involves Lys220 as general base for UDP-glucose alcohol oxidation and for oxyanion stabilization during formation and breakdown of the thiohemiacetal and thioester enzyme intermediates. Water coordinated to Asp280 deprotonates Cys276 to function as an aldehyde trap and also provides oxyanion stabilization. Glu161 is the Brønsted base catalytically promoting the thioester hydrolysis.
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Affiliation(s)
- Sigrid Egger
- Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, A-8010 Graz, Austria
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Yother J. Capsules ofStreptococcus pneumoniaeand Other Bacteria: Paradigms for Polysaccharide Biosynthesis and Regulation. Annu Rev Microbiol 2011; 65:563-81. [DOI: 10.1146/annurev.micro.62.081307.162944] [Citation(s) in RCA: 222] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Janet Yother
- Department of Microbiology, University of Alabama, Birmingham, Alabama 35294-2170;
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Rajakannan V, Lee HS, Chong SH, Ryu HB, Bae JY, Whang EY, Huh JW, Cho SW, Kang LW, Choe H, Robinson RC. Structural basis of cooperativity in human UDP-glucose dehydrogenase. PLoS One 2011; 6:e25226. [PMID: 21984906 PMCID: PMC3184952 DOI: 10.1371/journal.pone.0025226] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Accepted: 08/29/2011] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND UDP-glucose dehydrogenase (UGDH) is the sole enzyme that catalyzes the conversion of UDP-glucose to UDP-glucuronic acid. The product is used in xenobiotic glucuronidation in hepatocytes and in the production of proteoglycans that are involved in promoting normal cellular growth and migration. Overproduction of proteoglycans has been implicated in the progression of certain epithelial cancers, while inhibition of UGDH diminished tumor angiogenesis in vivo. A better understanding of the conformational changes occurring during the UGDH reaction cycle will pave the way for inhibitor design and potential cancer therapeutics. METHODOLOGY Previously, the substrate-bound of UGDH was determined to be a symmetrical hexamer and this regular symmetry is disrupted on binding the inhibitor, UDP-α-D-xylose. Here, we have solved an alternate crystal structure of human UGDH (hUGDH) in complex with UDP-glucose at 2.8 Å resolution. Surprisingly, the quaternary structure of this substrate-bound protein complex consists of the open homohexamer that was previously observed for inhibitor-bound hUGDH, indicating that this conformation is relevant for deciphering elements of the normal reaction cycle. CONCLUSION In all subunits of the present open structure, Thr131 has translocated into the active site occupying the volume vacated by the absent active water and partially disordered NAD+ molecule. This conformation suggests a mechanism by which the enzyme may exchange NADH for NAD+ and repolarize the catalytic water bound to Asp280 while protecting the reaction intermediates. The structure also indicates how the subunits may communicate with each other through two reaction state sensors in this highly cooperative enzyme.
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Affiliation(s)
- Venkatachalam Rajakannan
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore, Singapore
| | - Hui-Sun Lee
- Department of Physiology, University of Ulsan College of Medicine, Seoul, Korea
- Bio-Medical Institute of Technology, University of Ulsan College of Medicine, Seoul, Korea
| | - Seon-Ha Chong
- Department of Physiology, University of Ulsan College of Medicine, Seoul, Korea
- Bio-Medical Institute of Technology, University of Ulsan College of Medicine, Seoul, Korea
| | - Han-Bong Ryu
- Department of Physiology, University of Ulsan College of Medicine, Seoul, Korea
- Bio-Medical Institute of Technology, University of Ulsan College of Medicine, Seoul, Korea
| | - Ji-Young Bae
- Department of Physiology, University of Ulsan College of Medicine, Seoul, Korea
- Bio-Medical Institute of Technology, University of Ulsan College of Medicine, Seoul, Korea
| | - Eun-Young Whang
- Department of Biochemistry and Molecular Biology, University of Ulsan College of Medicine, Seoul, Korea
| | - Jae-Wan Huh
- Department of Biochemistry and Molecular Biology, University of Ulsan College of Medicine, Seoul, Korea
| | - Sung-Woo Cho
- Department of Biochemistry and Molecular Biology, University of Ulsan College of Medicine, Seoul, Korea
| | - Lin-Woo Kang
- Department of Advanced Technology Fusion, Kunkuk University, Seoul, Korea
| | - Han Choe
- Department of Physiology, University of Ulsan College of Medicine, Seoul, Korea
- Bio-Medical Institute of Technology, University of Ulsan College of Medicine, Seoul, Korea
- * E-mail:
| | - Robert C. Robinson
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore, Singapore
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Egger S, Chaikuad A, Kavanagh KL, Oppermann U, Nidetzky B. Structure and mechanism of human UDP-glucose 6-dehydrogenase. J Biol Chem 2011; 286:23877-87. [PMID: 21502315 PMCID: PMC3129169 DOI: 10.1074/jbc.m111.234682] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2011] [Revised: 04/06/2011] [Indexed: 11/21/2022] Open
Abstract
Elevated production of the matrix glycosaminoglycan hyaluronan is strongly implicated in epithelial tumor progression. Inhibition of synthesis of the hyaluronan precursor UDP-glucuronic acid (UDP-GlcUA) therefore presents an emerging target for cancer therapy. Human UDP-glucose 6-dehydrogenase (hUGDH) catalyzes, in two NAD(+)-dependent steps without release of intermediate aldehyde, the biosynthetic oxidation of UDP-glucose (UDP-Glc) to UDP-GlcUA. Here, we present a structural characterization of the hUGDH reaction coordinate using crystal structures of the apoenzyme and ternary complexes of the enzyme bound with UDP-Glc/NADH and UDP-GlcUA/NAD(+). The quaternary structure of hUGDH is a disc-shaped trimer of homodimers whose subunits consist of two discrete α/β domains with the active site located in the interdomain cleft. Ternary complex formation is accompanied by rigid-body and restrained movement of the N-terminal NAD(+) binding domain, sequestering substrate and coenzyme in their reactive positions through interdomain closure. By alternating between conformations in and out of the active site during domain motion, Tyr(14), Glu(161), and Glu(165) participate in control of coenzyme binding and release during 2-fold oxidation. The proposed mechanism of hUGDH involves formation and breakdown of thiohemiacetal and thioester intermediates whereby Cys(276) functions as the catalytic nucleophile. Stopped-flow kinetic data capture the essential deprotonation of Cys(276) in the course of the first oxidation step, allowing the thiolate side chain to act as a trap of the incipient aldehyde. Because thiohemiacetal intermediate accumulates at steady state under physiological reaction conditions, hUGDH inhibition might best explore ligand binding to the NAD(+) binding domain.
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Affiliation(s)
- Sigrid Egger
- From the Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, Petersgasse 12/1, A-8010 Graz, Austria
| | - Apirat Chaikuad
- the Structural Genomics Consortium, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Headington, Oxford OX3 7DQ, United Kingdom, and
| | - Kathryn L. Kavanagh
- the Structural Genomics Consortium, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Headington, Oxford OX3 7DQ, United Kingdom, and
| | - Udo Oppermann
- the Structural Genomics Consortium, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Headington, Oxford OX3 7DQ, United Kingdom, and
- the Botnar Research Centre, NIHR Oxford Biomedical Research Unit, University of Oxford, Oxford OX3 7LD, United Kingdom
| | - Bernd Nidetzky
- From the Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, Petersgasse 12/1, A-8010 Graz, Austria
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Structure of Burkholderia cepacia UDP-glucose dehydrogenase (UGD) BceC and role of Tyr10 in final hydrolysis of UGD thioester intermediate. J Bacteriol 2011; 193:3978-87. [PMID: 21602353 DOI: 10.1128/jb.01076-10] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Members of the Burkholderia cepacia complex (BCC) are serious respiratory pathogens in immunocompromised individuals and in patients with cystic fibrosis (CF). They are exceptionally resistant to many antimicrobial agents and have the capacity to spread between patients, leading to a decline in lung function and necrotizing pneumonia. BCC members often express a mucoid phenotype associated with the secretion of the exopolysaccharide (EPS) cepacian. There is much evidence supporting the fact that cepacian is a major virulence factor of BCC. UDP-glucose dehydrogenase (UGD) is responsible for the NAD-dependent 2-fold oxidation of UDP-glucose (UDP-Glc) to UDP-glucuronic acid (UDP-GlcA), which is a key step in cepacian biosynthesis. Here, we report the structure of BceC, determined at 1.75-Å resolution. Mutagenic studies were performed on the active sites of UGDs, and together with the crystallographic structures, they elucidate the molecular mechanism of this family of sugar nucleotide-modifying enzymes. Superposition with the structures of human and other bacterial UGDs showed an active site with high structural homology. This family contains a strictly conserved tyrosine residue (Y10 in BceC; shown in italics) within the glycine-rich motif (GXGYXG) of its N-terminal Rossmann-like domain. We constructed several BceC Y10 mutants, revealing only residual dehydrogenase activity and thus highlighting the importance of this conserved residue in the catalytic activity of BceC. Based on the literature of the UGD/GMD nucleotide sugar 6-dehydrogenase family and the kinetic and structural data we obtained for BceC, we determined Y10 as a key catalytic residue in a UGD rate-determining step, the final hydrolysis of the enzymatic thioester intermediate.
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31
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Chen YY, Ko TP, Lin CH, Chen WH, Wang AHJ. Conformational change upon product binding to Klebsiella pneumoniae UDP-glucose dehydrogenase: a possible inhibition mechanism for the key enzyme in polymyxin resistance. J Struct Biol 2011; 175:300-10. [PMID: 21536136 DOI: 10.1016/j.jsb.2011.04.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2011] [Revised: 03/22/2011] [Accepted: 04/14/2011] [Indexed: 10/18/2022]
Abstract
Cationic modification of lipid A with 4-amino-4-deoxy-L-arabinopyranose (L-Ara4N) allows the pathogen Klebsiella pneumoniae to resist the antibiotic polymyxin and other cationic antimicrobial peptides. UDP-glucose dehydrogenase (Ugd) catalyzes the NAD⁺-dependent twofold oxidation of UDP-glucose (UPG) to produce UDP-glucuronic acid (UGA), a requisite precursor in the biosynthesis of L-Ara4N and bacterial exopolysaccharides. Here we report five crystal structures of K. pneumoniae Ugd (KpUgd) in its apo form, in complex with UPG, UPG/NADH, two UGA molecules, and finally with a C-terminal His₆-tag. The UGA-complex structure differs from the others by a 14° rotation of the N-terminal domain toward the C-terminal domain, and represents a closed enzyme conformation. It also reveals that the second UGA molecule binds to a pre-existing positively charged surface patch away from the active site. The enzyme is thus inactivated by moving the catalytically important residues C253, K256 and D257 from their original positions. Kinetic data also suggest that KpUgd has multiple binding sites for UPG, and that UGA is a competitive inhibitor. The conformational changes triggered by UGA binding to the allosteric site can be exploited in designing potent inhibitors.
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Affiliation(s)
- Ying-Yin Chen
- Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan; Institute of Biochemical Sciences, National Taiwan University, Taipei 106, Taiwan
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32
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UDP-glucose dehydrogenase: structure and function of a potential drug target. Biochem Soc Trans 2011; 38:1378-85. [PMID: 20863317 DOI: 10.1042/bst0381378] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Biosynthesis of the glycosaminoglycan precursor UDP-α-D-glucuronic acid occurs through a 2-fold oxidation of UDP-α-D-glucose that is catalysed by UGDH (UDP-α-D-glucose 6-dehydrogenase). Structure-function relationships for UGDH and proposals for the enzymatic reaction mechanism are reviewed in the present paper, and structure-based sequence comparison is used for subclassification of UGDH family members. The eukaryotic group of enzymes (UGDH-II) utilize an extended C-terminal domain for the formation of complex homohexameric assemblies. The comparably simpler oligomerization behaviour of the prokaryotic group of enzymes (UGDH-I), in which dimeric forms prevail, is traced back to the lack of relevant intersubunit contacts and trimmings within the C-terminal region. The active site of UGDH contains a highly conserved cysteine residue, which plays a key role in covalent catalysis. Elevated glycosaminoglycan formation is implicated in a variety of human diseases, including the progression of tumours. The inhibition of synthesis of UDP-α-D-glucuronic acid using UGDH antagonists might therefore be a useful strategy for therapy.
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33
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Huang W, Llano J, Gauld JW. A DFT study on the catalytic mechanism of UDP-glucose dehydrogenase. CAN J CHEM 2010. [DOI: 10.1139/v10-044] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Uridine 5′-diphosphate glucuronic acid (UDPGlcUA) is a key intermediary metabolite in many species, including pathogenic bacteria and humans. It is biosynthesized from UDP-glucose (UDPGlc) by uridine diphosphate glucose dehydrogenase (UDPGlcDH) via a twofold two-electron–one-proton oxidation that successively transforms the 6-hydroxymethyl of glucopyranose into a formyl, and the latter into the final carboxylic function. The catalytic mechanism of UDPGlcDH was investigated using a large enzyme active-site model in combination with the B3LYP method and the polarizable continuum model (IEF-PCM) self-consistent reaction field. The latter was used to correct for the long-range electrostatic effect of the protein environment. The overall mechanism consists of four catalytic steps: (i) NAD+-dependent oxidation of glucose to glucuronaldehyde, (ii) nucleophilic addition of Cys260–SH to glucuronaldehyde to form a 6-thiohemiacetal intermediate, (iii) NAD+-dependent oxidation of the 6-thiohemiacetal to form a 6-thioester intermediate, and finally, (iv) hydrolysis of the 6-thioester to give glucuronic acid. In addition, this study also provides insight into the debated roles of Lys204 and Asp264, and the most likely protonation state of a reactive Michaelis complex of UDPGlcDH.
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Affiliation(s)
- WenJuan Huang
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, ON N9B 3P4, Canada
| | - Jorge Llano
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, ON N9B 3P4, Canada
| | - James W. Gauld
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, ON N9B 3P4, Canada
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Rocha J, Popescu AO, Sá-Correia I, Fialho AM, Frazão C. Cloning, expression, purification, crystallization and preliminary crystallographic studies of BceC, a UDP-glucose dehydrogenase from Burkholderia cepacia IST408. Acta Crystallogr Sect F Struct Biol Cryst Commun 2010; 66:269-71. [PMID: 20208157 PMCID: PMC2833033 DOI: 10.1107/s1744309109053500] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2009] [Accepted: 12/11/2009] [Indexed: 11/10/2022]
Abstract
Bacteria of the Burkholderia cepacia complex (Bcc) have emerged as important opportunistic pathogens, establishing lung infections in immunocompromised or cystic fibrosis patients. Bcc uses polysaccharide-biofilm production in order to evade the host immune response. The biofilm precursor UDP-glucuronic acid is produced by a twofold NAD(+)-dependent oxidation of UDP-glucose. In B. cepacia IST408 this enzymatic reaction is performed by the UDP-glucose dehydrogenase BceC, a 470-residue enzyme, the production and crystallization of which are described here. The crystals belonged to the orthorhombic space group P2(1)2(1)2(1) and contained four molecules in the asymmetric unit. Their crystallographic analysis at 2.09 A resolution and a molecular-replacement study are reported.
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Affiliation(s)
- Joana Rocha
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Apartado 127, 2781-901 Oeiras, Portugal
| | - Alma O. Popescu
- Institute for Biotechnology and Bioengineering, Center for Biological and Chemical Engineering, Instituto Superior Técnico, 1049-001 Lisbon, Portugal
| | - Isabel Sá-Correia
- Institute for Biotechnology and Bioengineering, Center for Biological and Chemical Engineering, Instituto Superior Técnico, 1049-001 Lisbon, Portugal
| | - Arsénio M. Fialho
- Institute for Biotechnology and Bioengineering, Center for Biological and Chemical Engineering, Instituto Superior Técnico, 1049-001 Lisbon, Portugal
| | - Carlos Frazão
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Apartado 127, 2781-901 Oeiras, Portugal
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Characterization of UDP-glucose dehydrogenase and UDP-glucose pyrophosphorylase mutants of Proteus mirabilis: defectiveness in polymyxin B resistance, swarming, and virulence. Antimicrob Agents Chemother 2010; 54:2000-9. [PMID: 20160049 DOI: 10.1128/aac.01384-09] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Proteus mirabilis is known to be highly resistant to the action of polymyxin B (PB). However, the mechanism underlying PB resistance is not clear. In this study, we used Tn5 transposon mutagenesis to identify genes that may affect PB resistance in P. mirabilis. Two genes, ugd and galU, which may encode UDP-glucose dehydrogenase (Ugd) and UDP-glucose pyrophosphorylase (GalU), respectively, were identified. Knockout mutants of ugd and galU were found to be extremely sensitive to PB, presumably because of alterations in lipopolysaccharide (LPS) structure and cell surface architecture in these mutants. These mutants were defective in swarming, expressed lower levels of virulence factor hemolysin, and had lower cell invasion ability. Complementation of the ugd or galU mutant with the full-length ugd or galU gene, respectively, led to the restoration of wild-type phenotypic traits. Interestingly, we found that the expression of Ugd and GalU was induced by PB through RppA, a putative response regulator of the bacterial two-component system that we identified previously. Mutation in either ugd or galU led to activation of RpoE, an extracytoplasmic function sigma factor that has been shown to be activated by protein misfolding and alterations in cell surface structure in other bacteria. Activation of RpoE or RpoE overexpression was found to cause inhibition of FlhDC and hemolysin expression. To our knowledge, this is the first report describing the roles and regulation of Ugd and GalU in P. mirabilis.
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Gu X, Wages CJ, Davis KE, Guyett PJ, Bar-Peled M. Enzymatic characterization and comparison of various poaceae UDP-GlcA 4-epimerase isoforms. J Biochem 2009; 146:527-34. [PMID: 19564155 DOI: 10.1093/jb/mvp099] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
UDP-alpha-D-galacturonic acid (UDP-GalA) is a key precursor for the synthesis of various bacterial and plant polysaccharides. UDP-glucuronic acid 4-epimerase (UGlcAE) catalyses the reversible conversion of UDP-alpha-D-glucuronic acid to UDP-GalA. UGlcAEs isolated from bacterial species have different biochemical properties when compared with the isoenzymes from the plant dicot species, Arabidopsis. However, little is known about the specificity of UGlcAE in Poaceae species. Therefore, we cloned and expressed in Escherichia coli several maize and rice UGlcAE genes, and compared their enzymatic properties with dicot homologs from Arabidopsis. Our data show that UGlcAE isoforms in different plant species have different enzymatic properties. For example, the Poaceae UGlcAE enzymes from rice and maize have significantly lower K(i) for UDP-xylose when compared with the Arabidopsis enzymes. The epimerases from different plant species are very specific and unlike their bacterial homolog in Klebsiella pneumoniae, can only use UDP-GlcA or UDP-GalA as their substrate. This study demonstrates that although members of the plant UGlcAE isoforms are highly conserved, the in vitro enzymatic activity of specific Poaceae isoform(s) may be regulated differently by specific nucleotide or nucleotide sugar.
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Affiliation(s)
- Xiaogang Gu
- Department of Plant Biology, University of Georgia, Athens, GA 30602-4712, USA
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Kluger R, Rathgeber S. Catalyzing separation of carbon dioxide in thiamin diphosphate-promoted decarboxylation. FEBS J 2008; 275:6089-100. [DOI: 10.1111/j.1742-4658.2008.06739.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Huh JW, Yang SJ, Hwang EY, Choi MM, Lee HJ, Kim EA, Choi SY, Choi J, Hong HN, Cho SW. Alteration of the quaternary structure of human UDP-glucose dehydrogenase by a double mutation. BMB Rep 2008; 40:690-6. [PMID: 17927902 DOI: 10.5483/bmbrep.2007.40.5.690] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
There are conflicting views for the polymerization process of human UDP-glucose dehydrogenase (UGDH) and no clear evidence has been reported yet. Based on crystal coordinates for Streptococcus pyogenes UGDH, we made double mutant A222Q/S233G. The double mutagenesis had no effects on expression, stability, and secondary structure. Interestingly, A222Q/S233G was a dimeric form and showed an UGDH activity, although it showed increased Km values for substrates. These results suggest that Ala222 and Ser233 play an important role in maintaining the hexameric structure and the reduced binding affinities for substrates are attributable to its altered subunit communication although quaternary structure may not be critical for catalysis.
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Affiliation(s)
- Jae-Wan Huh
- Department of Biochemistry and Molecular Biology, University of Ulsan College of Medicine, Seoul 138-736, Korea
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Ren H, Dover LG, Islam ST, Alexander DC, Chen JM, Besra GS, Liu J. Identification of the lipooligosaccharide biosynthetic gene cluster from Mycobacterium marinum. Mol Microbiol 2007; 63:1345-59. [PMID: 17302813 DOI: 10.1111/j.1365-2958.2007.05603.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Lipooligosaccharides (LOSs) are antigenic glycolipids that are present in some species of Mycobacterium including the Canetti strain of M. tuberculosis. The core LOS structures from several mycobacterial organisms have been established, but the biosynthetic pathways of LOSs remain unknown. In this study, we describe two transposon insertion mutants of M. marinum that exhibit altered colony morphology. Cell wall analysis reveals that the MRS1271 mutant is defective in the synthesis of LOS-II, whereas the MRS1178 mutant accumulates an intermediate between LOS-I and -II. The genetic lesions were localized to two genes, MM2309 and MM2332. MM2309 encodes a UDP-glucose dehydrogenase that is involved in the synthesis of d-xylose. MM2332 is predicted to encode a decarboxylase. These two genes and a previously identified losA gene are localized in a gene cluster likely to be involved in the biosynthesis of LOSs. Our results also show that LOSs play an important role in sliding motility, biofilm formation, and infection of host macrophages. Taken together, our studies have identified, for the first time, a LOS biosynthetic locus. This is an important step in assessing the differential distribution of LOSs among Mycobacterium species and understanding the role of LOSs in mycobacterial virulence.
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Affiliation(s)
- Huiping Ren
- Department of Medical Genetics and Microbiology, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
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Granja AT, Popescu A, Marques AR, Sá-Correia I, Fialho AM. Biochemical characterization and phylogenetic analysis of UDP-glucose dehydrogenase from the gellan gum producer Sphingomonas elodea ATCC 31461. Appl Microbiol Biotechnol 2007; 76:1319-27. [PMID: 17668199 DOI: 10.1007/s00253-007-1112-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2007] [Revised: 07/03/2007] [Accepted: 07/04/2007] [Indexed: 10/23/2022]
Abstract
Sphingomonas elodea ATCC 31461 synthesizes in high yield the exopolysaccharide gellan, which is a water-soluble gelling agent with many applications. In this study, we describe the cloning and sequence analysis of the ugdG gene, encoding a UDP-glucose dehydrogenase (47.2 kDa; UDPG-DH; EC 1.1.1.22), required for the synthesis of the gellan gum precursor UDP-glucuronic acid. UgdG protein shows homology to members of the UDP-glucose/GDP-mannose dehydrogenase superfamily. The Neighbor-Joining method was used to determine phylogenetic relationships among prokaryotic and eukaryotic UDPG-DHs. UgdG from S. elodea and UDPG-DHs from Novosphingobium, Zymomonas, Agrobacterium, and Caulobacter species form a divergent phylogenetic group with a close evolutionary relationship with eukaryotic UDPG-DHs. The ugdG gene was recombinantly expressed in Escherichia coli with and N-terminal 6-His tag and purified for biochemical characterization. The enzyme has an optimum temperature and pH of 37 degrees C and 8.7, respectively. The estimated apparent K(m) values for UDP-glucose and NAD(+) were 0.87 and 0.4 mM, respectively. DNA sequencing of chromosomal regions adjacent to ugdG gene and sequence similarity studies suggests that this gene maps together with others presumably involved in the biosynthesis of S. elodea cell wall polysaccharides.
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Affiliation(s)
- Ana Teresa Granja
- IBB - Institute for Biotechnology and Bioengineering, Centre for Biological and Chemical Engineering, Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisbon, Portugal
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41
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Xayarath B, Yother J. Mutations blocking side chain assembly, polymerization, or transport of a Wzy-dependent Streptococcus pneumoniae capsule are lethal in the absence of suppressor mutations and can affect polymer transfer to the cell wall. J Bacteriol 2007; 189:3369-81. [PMID: 17322316 PMCID: PMC1855910 DOI: 10.1128/jb.01938-06] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Extracellular polysaccharides of many bacteria are synthesized by the Wzy polymerase-dependent mechanism, where long-chain polymers are assembled from undecaprenyl-phosphate-linked repeat units on the outer face of the cytoplasmic membrane. In gram-positive bacteria, Wzy-dependent capsules remain largely cell associated via membrane and peptidoglycan linkages. Like many Wzy-dependent capsules, the Streptococcus pneumoniae serotype 2 capsule is branched. In this study, we found that deletions of cps2K, cps2J, or cps2H, which encode a UDP-glucose dehydrogenase necessary for side chain synthesis, the putative Wzx transporter (flippase), and the putative Wzy polymerase, respectively, were obtained only in the presence of suppressor mutations. Most of the suppressor mutations were in cps2E, which encodes the initiating glycosyltransferase for capsule synthesis. The cps2K mutants containing the suppressor mutations produced low levels of high-molecular-weight polymer that was detected only in membrane fractions. cps2K-repaired mutants exhibited only modest increases in capsule production due to the effect of the secondary mutation, but capsule was detectable in both membrane and cell wall fractions. Lethality of the cps2K, cps2J, and cps2H mutations was likely due to sequestration of undecaprenyl-phosphate in the capsule pathway and either preclusion of its turnover for utilization in essential pathways or destabilization of the membrane due to an accumulation of lipid-linked intermediates. The results demonstrate that proper polymer assembly requires not only a functional transporter and polymerase but also complete repeat units. A central role for the initiating glycosyltransferase in controlling capsule synthesis is also suggested.
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Affiliation(s)
- Bobbi Xayarath
- Department of Microbiology, 845 19th Street South, BBRB 661/12, Birmingham, AL 35294-2170, USA
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Blanch M, Legaz ME, Vicente C. Purification and properties of an unusual UDP-glucose dehydrogenase, NADPH-dependent, from Xanthomonas albilineans. Microbiol Res 2006; 163:362-71. [PMID: 17010583 DOI: 10.1016/j.micres.2006.07.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2006] [Revised: 07/12/2006] [Accepted: 07/18/2006] [Indexed: 11/28/2022]
Abstract
Xanthomonas albilineans produces a UDP-glucose dehydrogenase growing on sucrose. The enzyme oxidizes UDP-glucose to UDP-glucuronic acid by using molecular oxygen and NADPH. Kinetics of enzymatic oxydation of NADPH is linearly dependent on the amount of oxygen supplied. The enzyme has been purified at homogeneity. The value of pI of the purified enzyme is 8.98 and its molecular mass has been estimated as about 14 kDa. The enzyme shows a michaelian kinetics for UDP-glucose concentrations. The value of K(m) for UDP-glucose is 0.87 mM and 0.26 mM for NADPH, although the enzyme has three different sites to interact with NADPH. The enzyme is inhibited by UDP-glucose concentrations higher than 1.3 mM. N-Terminal sequence has been determined as IQPYNH.
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Affiliation(s)
- María Blanch
- Laboratory of Plant Physiology, Faculty of Biology, Complutense University, Madrid, Spain
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43
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Zhang H, Zhou Y, Bao H, Liu HW. Vi antigen biosynthesis in Salmonella typhi: characterization of UDP-N-acetylglucosamine C-6 dehydrogenase (TviB) and UDP-N-acetylglucosaminuronic acid C-4 epimerase (TviC). Biochemistry 2006; 45:8163-73. [PMID: 16800641 PMCID: PMC2515272 DOI: 10.1021/bi060446d] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Vi antigen, the virulence factor of Salmonella typhi, has been used clinically as a molecular vaccine. TviB and TviC are two enzymes involved in the formation of Vi antigen, a linear polymer consisting of alpha-1,4-linked N-acetylgalactosaminuronate. Protein sequence analysis suggests that TviB is a dehydrogenase and TviC is an epimerase. Both enzymes are expected to be NAD(+) dependent. In order to verify their functions, TviB and TviC were cloned, expressed in Escherichia coli, and characterized. The C-terminal His(6)-tagged TviB protein, purified from soluble cell fractions in the presence of 10 mM DTT, shows UDP-N-acetylglucosamine 6-dehydrogenase activity and is capable of catalyzing the conversion of UDP-N-acetylglucosamine (UDP-GlcNAc) to UDP-N-acetylglucosaminuronic acid (UDP-GlcNAcA) with a k(cat) value of 15.5 +/- 1.0 min(-)(1). The K(m) values of TviB for UDP-GlcNAc and NAD(+) are 77 +/- 9 microM and 276 +/- 52 microM, respectively. TviC, purified as C-terminal hexahistidine-tagged protein, shows UDP-GlcNAcA 4-epimerase and UDP-N-acetylgalactosamine (UDP-GalNAc) 4-epimerase activities. The K(m) values of TviC for UDP-GlcNAcA and UDP-N-acetylgalactosaminuronic acid (UDP-GalNAcA) are 20 +/- 1 microM and 42 +/- 2 microM, respectively. The k(cat) value for the conversion of UDP-GlcNAcA to UDP-GalNAcA is 56.8 +/- 0.5 min(-)(1), while that for the reverse reaction is 39.1 +/- 0.6 min(-)(1). These results show that the biosynthesis of Vi antigen is initiated by the TviB-catalyzed oxidation of UDP-GlcNAc to UDP-GalNAc, followed by the TviC-catalyzed epimerization at C-4 to form UDP-GalNAcA, which serves as the building block for the formation of Vi polymer. These results set the stage for future in vitro biosynthesis of Vi antigen. These enzymes may also be drug targets to inhibit Vi antigen production.
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Affiliation(s)
| | | | | | - Hung-wen Liu
- *To whom correspondence and reprint requests should be addressed. Phone: 512-232-7811. Fax: 512-471-2746. E-mail:
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44
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Vigetti D, Ori M, Viola M, Genasetti A, Karousou E, Rizzi M, Pallotti F, Nardi I, Hascall VC, De Luca G, Passi A. Molecular cloning and characterization of UDP-glucose dehydrogenase from the amphibian Xenopus laevis and its involvement in hyaluronan synthesis. J Biol Chem 2006; 281:8254-63. [PMID: 16418163 DOI: 10.1074/jbc.m508516200] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
UDP-glucose dehydrogenase (UGDH) supplies the cell with UDP-glucuronic acid (UDP-GlcUA), a precursor of glycosaminoglycan and proteoglycan synthesis. Here we reported the cloning and the characterization of the UGDH from the amphibian Xenopus laevis that is one of the model organisms for developmental biology. We found that X. laevis UGDH (xUGDH) maintained a very high degree of similarity with other known UGDH sequences both at the genomic and the protein levels. Also its kinetic parameters are similar to those of UGDH from other species. During X. laevis development, UDGH is always expressed but clearly increases its mRNA levels at the tail bud stage (i.e. 30 h post-fertilization). This result fits well with our previous observation that hyaluronan, a glycosaminoglycan that is synthesized using UDP-GlcUA and UDP-N-acetylglucosamine, is abundantly detected at this developmental stage. The expression of UGDH was found to be related to hyaluronan synthesis. In human smooth muscle cells the overexpression of xUGDH or endogenous abrogation of UGDH modulated hyaluronan synthesis specifically. Our findings were confirmed by in vivo experiments where the silencing of xUGDH in X. laevis embryos decreased glycosaminoglycan synthesis causing severe embryonic malformations because of a defective gastrulation process.
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Affiliation(s)
- Davide Vigetti
- Dipartimento di Scienze Biomediche Sperimentali e Cliniche, Università degli Studi dell'Insubria, via J. H. Dunant 5, 21100 Varese, Italy
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45
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Mijakovic I, Petranovic D, Deutscher J. How tyrosine phosphorylation affects the UDP-glucose dehydrogenase activity of Bacillus subtilis YwqF. J Mol Microbiol Biotechnol 2005; 8:19-25. [PMID: 15741737 DOI: 10.1159/000082077] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The UDP-glucose dehydrogenase activity of Bacillus subtilis YwqF is regulated by reversible phosphorylation on a tyrosine residue. This reaction, which is catalyzed by the protein-tyrosine kinase YwqD, activates the enzyme, while dephosphorylation of phosphotyrosine-YwqF by the phosphotyrosine-protein phosphatase YwqE reduces its enzyme activity. Our kinetic data indicate that the phosphorylated and unphosphorylated forms of YwqF differ in binding the substrates. The UDP-glucose dehydrogenase reaction catalyzed by YwqF is inhibited by one of its substrates, UDP-glucose, and the extent of this inhibition seems to be reduced upon YwqF phosphorylation. We propose that this effect could at least partly account for the observed activation of YwqF induced by tyrosine phosphorylation. Potential physiological implications of this finding are discussed.
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Affiliation(s)
- Ivan Mijakovic
- Microbiologie et Génétique Moléculaire, CNRS/INRA/INA-PG UMR 2585, Thiverval-Grignon, France.
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Bar-Peled M, Griffith C, Ory J, Doering T. Biosynthesis of UDP-GlcA, a key metabolite for capsular polysaccharide synthesis in the pathogenic fungus Cryptococcus neoformans. Biochem J 2004; 381:131-6. [PMID: 15030319 PMCID: PMC1133770 DOI: 10.1042/bj20031075] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2003] [Revised: 03/18/2004] [Accepted: 03/19/2004] [Indexed: 11/17/2022]
Abstract
UDP-glucose dehydrogenase catalyses the conversion of UDP-glucose into UDP-GlcA, a critical precursor for glycan synthesis across evolution. We have cloned the gene encoding this important enzyme from the opportunistic pathogen Cryptococcus neoformans. In this fungus, UDP-GlcA is required for the synthesis of capsule polysaccharides, which in turn are essential for virulence. The gene was expressed in Escherichia coli and the 51.3-kDa recombinant protein from wild-type and five mutants was purified for analysis. The cryptococcal enzyme is strongly inhibited by UDP-xylose and NADH, has highest activity at pH 7.5 and demonstrates Km (app) values of 0.1 and 1.5 mM for NAD+ and UDP-glucose respectively. Its activity was significantly decreased by mutations in the putative sites of NAD+ and UDP-glucose binding. Unlike previously reported eukaryotic UDP-glucose dehydrogenases, which are hexamers, the cryptococcal enzyme is a dimer.
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Affiliation(s)
- Maor Bar-Peled
- *Complex Carbohydrate Research Center of the University of Georgia, 220 Riverbend Road, Athens, GA 30602-4712, U.S.A
| | - Cara L. Griffith
- †Department of Molecular Microbiology, Campus Box 8230, 660 South Euclid Avenue, St. Louis, MO 63110-1093, U.S.A
| | - Jeramia J. Ory
- †Department of Molecular Microbiology, Campus Box 8230, 660 South Euclid Avenue, St. Louis, MO 63110-1093, U.S.A
| | - Tamara L. Doering
- †Department of Molecular Microbiology, Campus Box 8230, 660 South Euclid Avenue, St. Louis, MO 63110-1093, U.S.A
- To whom correspondence should be addressed (e-mail )
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47
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Huh JW, Yoon HY, Lee HJ, Choi WB, Yang SJ, Cho SW. Importance of Gly-13 for the coenzyme binding of human UDP-glucose dehydrogenase. J Biol Chem 2004; 279:37491-8. [PMID: 15247292 DOI: 10.1074/jbc.m404234200] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
UDP-glucose dehydrogenase (UGDH) is the unique pathway enzyme furnishing in vertebrates UDP-glucuronate for numerous transferases. In this report, we have identified an NAD(+)-binding site within human UGDH by photoaffinity labeling with a specific probe, [(32)P]nicotinamide 2-azidoadenosine dinucleotide (2N(3) NAD(+)), and cassette mutagenesis. For this work, we have chemically synthesized a 1509-base pair gene encoding human UGDH and expressed it in Escherichia coli as a soluble protein. Photolabel-containing peptides were generated by photolysis followed by tryptic digestion and isolated using the phosphopeptide isolation kit. Photolabeling of these peptides was effectively prevented by the presence of NAD(+) during photolysis, demonstrating a selectivity of the photoprobe for the NAD(+)-binding site. Amino acid sequencing and compositional analysis identified the NAD(+)-binding site of UGDH as the region containing the sequence ICCIGAXYVGGPT, corresponding to Ile-7 through Thr-19 of the amino acid sequence of human UGDH. The unidentified residue, X, can be designated as a photolabeled Gly-13 because the sequences including the glycine residue in question have a complete identity with those of other UGDH species known. The importance of Gly-13 residue in the binding of NAD(+) was further examined with a G13E mutant by cassette mutagenesis. The mutagenesis at Gly-13 had no effects on the expression or stability of the mutant. Enzyme activity of the G13E point mutant was not measurable under normal assay conditions, suggesting an important role for the Gly-13 residue. No incorporation of [(32)P]2N(3)NAD(+) was observed for the G13E mutant. These results indicate that Gly-13 plays an important role for efficient binding of NAD(+) to human UGDH.
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Affiliation(s)
- Jae-Wan Huh
- Department of Biochemistry and Molecular Biology, University of Ulsan College of Medicine, Seoul 138-736, Korea
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48
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Bravo IG, Reglero A. Application of a normalised plot to the study of ter ter enzyme systems. Biochimie 2004; 86:463-9. [PMID: 15308335 DOI: 10.1016/j.biochi.2004.06.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2003] [Accepted: 06/17/2004] [Indexed: 11/30/2022]
Abstract
The kinetic characterisation of multisubstrate systems is not a trivial task. Common approaches simplify the experimental procedures by sequentially fixing saturating concentrations of different substrates/products, thereby attempting to isolate the influence of the varying molecule. Even after such tedious work, only apparent Km values can be determined, preventing serious comparison among differential substrate behaviours. Moreover, the choice among rival kinetic models is not statistically guaranteed; instead, classical tools such as re-plots continue to be used. Here, we report the application of a normalisation of kinetic data, formerly applied to simpler systems, to the description of ter ter systems. This data treatment is able to provide true Km values and a reliable description of the system, at the same time reducing the experimental work and statistically supporting the choice of kinetic schemes.
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Affiliation(s)
- Ignacio G Bravo
- Deustches Krebsforschungszentrum, Im Neuenheimer Feld 242, 69120 Heidelberg, Germany.
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49
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Miller WL, Wenzel CQ, Daniels C, Larocque S, Brisson JR, Lam JS. Biochemical characterization of WbpA, a UDP-N-acetyl-D-glucosamine 6-dehydrogenase involved in O-antigen biosynthesis in Pseudomonas aeruginosa PAO1. J Biol Chem 2004; 279:37551-8. [PMID: 15226302 DOI: 10.1074/jbc.m404749200] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
WbpA (PA3159) is an enzyme involved in the biosynthesis of unusual di-N-acetyl-d-mannosaminuronic acid-derived sugar nucleotides found in the O antigen of Pseudomonas aeruginosa PAO1 (serotype O5). The wbpA gene that encodes this enzyme was cloned into pET-28a, overexpressed as a histidine-tagged fusion protein, and purified by nickel chelation chromatography. Capillary electrophoresis was used to examine substrate conversion by WbpA, and the data revealed that WbpA is a UDP-N-acetyl-D-glucosamine 6-dehydrogenase (EC 1.1.1.136), which uses NAD(+) as a coenzyme. The enzyme reaction product was purified by HPLC and analyzed using NMR spectroscopy. Our results showed unequivocally that the product of the WbpA reaction is UDP-N-acetyl-d-glucosaminuronic acid. WbpA requires either NH(4)(+) or K(+) for activity and the accompanying anions exert secondary effects on activity consistent with their ranking in the Hofmeister series. Kinetic analysis showed positive cooperativity with respect to UDP-N-acetyl-d-glucosamine binding with a K(0.5) of 94 microM, a k(cat) of 86 min(-1), and a Hill coefficient of 1.8. In addition, WbpA has a K(0.5) for NAD(+) of 220 microM, a k(cat) of 86 min(-1), and a Hill coefficient of 1.1. The oligomerization state of WbpA was analyzed by gel filtration, dynamic light scattering, and analytical ultracentrifugation, with all three techniques indicating that WbpA exists as a trimer in solution. However, tertiary structure predictions suggested a tetramer, which was supported by data from transmission electron microscopy. The electron micrograph of negatively stained WbpA samples revealed structures with 4-fold symmetry.
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Affiliation(s)
- Wayne L Miller
- Department of Microbiology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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50
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Sommer BJ, Barycki JJ, Simpson MA. Characterization of human UDP-glucose dehydrogenase. CYS-276 is required for the second of two successive oxidations. J Biol Chem 2004; 279:23590-6. [PMID: 15044486 DOI: 10.1074/jbc.m401928200] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
UDP-glucose dehydrogenase (UGDH) catalyzes two oxidations of UDP-glucose to yield UDP-glucuronic acid. Pathological overproduction of extracellular matrix components may be linked to the availability of UDP-glucuronic acid; therefore UGDH is an intriguing therapeutic target. Specific inhibition of human UGDH requires detailed knowledge of its catalytic mechanism, which has not been characterized. In this report, we have cloned, expressed, and affinity-purified the human enzyme and determined its steady state kinetic parameters. The human enzyme is active as a hexamer with values for Km and Vmax that agree well with those reported for a bovine homolog. We used crystal coordinates for Streptococcus pyogenes UGDH in complex with NAD+ cofactor and UDP-glucose substrate to generate a model of the enzyme active site. Based on this model, we selected Cys-276 and Lys-279 as likely catalytic residues and converted them to serine and alanine, respectively. Enzymatic activity of C276S and K279A point mutants was not measurable under normal assay conditions. Rate constants measured over several hours demonstrated that K279A continued to turn over, although 250-fold more slowly than wild type enzyme. C276S, however, performed only a single round of oxidation, indicating that it is essential for the second oxidation. This result is consistent with the postulated role of Cys-276 as a catalytic residue and supports its position in the reaction mechanism for the human enzyme. Lys-279 is likely to have a role in positioning active site residues and in maintaining the hexameric quaternary structure.
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Affiliation(s)
- Brandi J Sommer
- Department of Biochemistry, University of Nebraska, Lincoln, Nebraska 68588-0664, USA
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