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Sharon I, Schmeing TM. Bioinformatics of cyanophycin metabolism genes and characterization of promiscuous isoaspartyl dipeptidases that catalyze the final step of cyanophycin degradation. Sci Rep 2023; 13:8314. [PMID: 37221236 DOI: 10.1038/s41598-023-34587-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 05/03/2023] [Indexed: 05/25/2023] Open
Abstract
Cyanophycin is a bacterial biopolymer used for storage of fixed nitrogen. It is composed of a backbone of L-aspartate residues with L-arginines attached to each of their side chains. Cyanophycin is produced by cyanophycin synthetase 1 (CphA1) using Arg, Asp and ATP, and is degraded in two steps. First, cyanophycinase breaks down the backbone peptide bonds, releasing β-Asp-Arg dipeptides. Then, these dipeptides are broken down into free Asp and Arg by enzymes with isoaspartyl dipeptidase activity. Two bacterial enzymes are known to possess promiscuous isoaspartyl dipeptidase activity: isoaspartyl dipeptidase (IadA) and isoaspartyl aminopeptidase (IaaA). We performed a bioinformatic analysis to investigate whether genes for cyanophycin metabolism enzymes cluster together or are spread around the microbial genomes. Many genomes showed incomplete contingents of known cyanophycin metabolizing genes, with different patterns in various bacterial clades. Cyanophycin synthetase and cyanophycinase are usually clustered together when recognizable genes for each are found within a genome. Cyanophycinase and isoaspartyl dipeptidase genes typically cluster within genomes lacking cphA1. About one-third of genomes with genes for CphA1, cyanophycinase and IaaA show these genes clustered together, while the proportion is around one-sixth for CphA1, cyanophycinase and IadA. We used X-ray crystallography and biochemical studies to characterize an IadA and an IaaA from two such clusters, in Leucothrix mucor and Roseivivax halodurans, respectively. The enzymes retained their promiscuous nature, showing that being associated with cyanophycin-related genes did not make them specific for β-Asp-Arg dipeptides derived from cyanophycin degradation.
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Affiliation(s)
- Itai Sharon
- Department of Biochemistry and Centre de recherche en biologie structurale, McGill University, Montréal, QC, H3G 0B1, Canada
| | - T Martin Schmeing
- Department of Biochemistry and Centre de recherche en biologie structurale, McGill University, Montréal, QC, H3G 0B1, Canada.
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2
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Wang J, Guo C, Meng Z, Zwan MD, Chen X, Seelow S, Lundström SL, Rodin S, Teunissen CE, Zubarev RA. Testing the link between isoaspartate and Alzheimer's disease etiology. Alzheimers Dement 2022; 19:1491-1502. [PMID: 35924765 DOI: 10.1002/alz.12735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 05/24/2022] [Accepted: 05/25/2022] [Indexed: 11/09/2022]
Abstract
Isoaspartate (isoAsp) is a damaging amino acid residue formed in proteins as a result of spontaneous deamidation. IsoAsp disrupts protein structures, making them prone to aggregation. Here we strengthened the link between isoAsp and Alzheimer's disease (AD) by novel approaches to isoAsp analysis in human serum albumin (HSA), the most abundant blood protein and a major carrier of amyloid beta (Aβ) and phosphorylated tau (p-tau) in blood. We discovered a reduced amount of anti-isoAsp antibodies (P < 0.0001), an elevated isoAsp level in HSA (P < 0.001), more HSA aggregates (P < 0.0001), and increased levels of free Aβ (P < 0.01) in AD blood compared to controls. We also found that deamidation significantly reduces HSA capacity to bind with Aβ and p-tau (P < 0.05). These suggest the presence in AD of a bottleneck in clearance of Aβ and p-tau, leading to their increased concentrations in the brain and facilitating their aggregations there.
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Affiliation(s)
- Jijing Wang
- Department of Medical Biophysics and Biochemistry, Karolinska Institutet, Stockholm, Sweden
| | - Cong Guo
- Department of Physics and International Centre for Quantum and Molecular Structures, College of Sciences, Shanghai University, Shanghai, China
| | - Zhaowei Meng
- Department of Medical Biophysics and Biochemistry, Karolinska Institutet, Stockholm, Sweden
| | - Marissa D Zwan
- Neurochemistry Laboratory, Department of Clinical Chemistry, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam UMC, Amsterdam, The Netherlands
| | - Xin Chen
- Department of Physics and International Centre for Quantum and Molecular Structures, College of Sciences, Shanghai University, Shanghai, China
| | - Sven Seelow
- Department of Medical Biophysics and Biochemistry, Karolinska Institutet, Stockholm, Sweden
| | - Susanna L Lundström
- Department of Medical Biophysics and Biochemistry, Karolinska Institutet, Stockholm, Sweden
| | - Sergey Rodin
- Department of Medical Biophysics and Biochemistry, Karolinska Institutet, Stockholm, Sweden.,Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
| | - Charlotte E Teunissen
- Neurochemistry Laboratory, Department of Clinical Chemistry, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam UMC, Amsterdam, The Netherlands
| | - Roman A Zubarev
- Department of Medical Biophysics and Biochemistry, Karolinska Institutet, Stockholm, Sweden.,Endocrinology Research Centre, Moscow, Russian Federation.,Department of Pharmacological & Technological Chemistry, I.M. Sechenov First Moscow State Medical University, Moscow, Russian Federation
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3
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Zhang S, Fu B, Xiong Y, Zhao Q, Xu S, Lin X, Wu H. Tgm2 alleviates LPS-induced apoptosis by inhibiting JNK/BCL-2 signaling pathway through interacting with Aga in macrophages. Int Immunopharmacol 2021; 101:108178. [PMID: 34607226 DOI: 10.1016/j.intimp.2021.108178] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 09/08/2021] [Accepted: 09/18/2021] [Indexed: 12/19/2022]
Abstract
Sepsis is an unusual systemic infection caused by bacteria, which is a life-threatening organ dysfunction. The innate immune system plays an important role in this process; however, the specific mechanisms remain unclear. Using the LPS + treated mouse model, we found that the survival rate of Tgm2-/- mice was lower than that of the control group, while the inflammation was much higher. We further showed that Tgm2 suppressed apoptosis by inhibiting the JNK/BCL-2 signaling pathway. More importantly, Tgm2 interacted with Aga and regulated mitochondria-mediated apoptosis induced by LPS. Our findings elucidated a protective mechanism of Tgm2 during LPS stimulation and may provide a new reference target for the development of novel anti-infective drugs from the perspective of host immunity.
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Affiliation(s)
- Shanfu Zhang
- School of Life Sciences, Chongqing University, Chongqing 401331, China
| | - Beibei Fu
- School of Life Sciences, Chongqing University, Chongqing 401331, China
| | - Yan Xiong
- School of Life Sciences, Chongqing University, Chongqing 401331, China
| | - Qingting Zhao
- School of Life Sciences, Chongqing University, Chongqing 401331, China
| | - Shiyao Xu
- School of Life Sciences, Chongqing University, Chongqing 401331, China
| | - Xiaoyuan Lin
- School of Life Sciences, Chongqing University, Chongqing 401331, China.
| | - Haibo Wu
- School of Life Sciences, Chongqing University, Chongqing 401331, China.
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Direct Addition of Amides to Glycals Enabled by Solvation‐Insusceptible 2‐Haloazolium Salt Catalysis. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201907129] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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5
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Nakatsuji Y, Kobayashi Y, Takemoto Y. Direct Addition of Amides to Glycals Enabled by Solvation-Insusceptible 2-Haloazolium Salt Catalysis. Angew Chem Int Ed Engl 2019; 58:14115-14119. [PMID: 31392793 DOI: 10.1002/anie.201907129] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 07/24/2019] [Indexed: 01/12/2023]
Abstract
The direct 2-deoxyglycosylation of nucleophiles with glycals leads to biologically and pharmacologically important 2-deoxysugar compounds. Although the direct addition of hydroxyl and sulfonamide groups have been well developed, the direct 2-deoxyglycosylation of amide groups has not been reported to date. Herein, we show the first direct 2-deoxyglycosylation of amide groups using a newly designed Brønsted acid catalyst under mild conditions. Through mechanistic investigations, we discovered that the amide group can inhibit acid catalysts, and the inhibition has made the 2-deoxyglycosylation reaction difficult. Diffusion-ordered two-dimensional NMR spectroscopy analysis implied that the 2-chloroazolium salt catalyst was less likely to form aggregates with amides in comparison to other acid catalysts. The chlorine atom and the extended π-scaffold of the catalyst played a crucial role for this phenomenon. This relative insusceptibility to inhibition by amides is more responsible for the catalytic activity than the strength of the acidity.
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Affiliation(s)
- Yuya Nakatsuji
- Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29 Shimoadachi-cho, Yoshida, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Yusuke Kobayashi
- Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29 Shimoadachi-cho, Yoshida, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Yoshiji Takemoto
- Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29 Shimoadachi-cho, Yoshida, Sakyo-ku, Kyoto, 606-8501, Japan
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Pande S, Lakshminarasimhan D, Guo HC. Crystal structure of a mutant glycosylasparaginase shedding light on aspartylglycosaminuria-causing mechanism as well as on hydrolysis of non-chitobiose substrate. Mol Genet Metab 2017; 121:150-156. [PMID: 28457719 PMCID: PMC5504686 DOI: 10.1016/j.ymgme.2017.04.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 04/18/2017] [Accepted: 04/18/2017] [Indexed: 10/19/2022]
Abstract
Glycosylasparaginase (GA) is an amidase that cleaves Asn-linked glycoproteins in lysosomes. Deficiency of this enzyme causes accumulation of glycoasparagines in lysosomes of cells, resulting in a genetic condition called aspartylglycosaminuria (AGU). To better understand the mechanism of a disease-causing mutation with a single residue change from a glycine to an aspartic acid, we generated a model mutant enzyme at the corresponding position (named G172D mutant). Here we report a 1.8Å resolution crystal structure of mature G172D mutant and analyzed the reason behind its low hydrolase activity. Comparison of mature G172D and wildtype GA models reveals that the presence of Asp 172 near the catalytic site affects substrate catabolism in mature G172D, making it less efficient in substrate processing. Also recent studies suggest that GA is capable of processing substrates that lack a chitobiose (Glycan, N-acetylchiobios, NAcGlc) moiety, by its exo-hydrolase activity. The mechanism for this type of catalysis is not yet clear. l-Aspartic acid β-hydroxamate (β-AHA) is a non-chitobiose substrate that is known to interact with GA. To study the underlying mechanism of non-chitobiose substrate processing, we built a GA-β-AHA complex structure by comparing to a previously published G172D mutant precursor in complex with a β-AHA molecule. A hydrolysis mechanism of β-AHA by GA is proposed based on this complex model.
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Affiliation(s)
- Suchita Pande
- Department of Biological Sciences, University of Massachusetts Lowell, 1 University Avenue, Lowell, MA 01854, USA
| | - Damodharan Lakshminarasimhan
- Department of Biological Sciences, University of Massachusetts Lowell, 1 University Avenue, Lowell, MA 01854, USA
| | - Hwai-Chen Guo
- Department of Biological Sciences, University of Massachusetts Lowell, 1 University Avenue, Lowell, MA 01854, USA.
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Cachumba JJM, Antunes FAF, Peres GFD, Brumano LP, Santos JCD, Da Silva SS. Current applications and different approaches for microbial l-asparaginase production. Braz J Microbiol 2016; 47 Suppl 1:77-85. [PMID: 27866936 PMCID: PMC5156506 DOI: 10.1016/j.bjm.2016.10.004] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 09/06/2016] [Indexed: 01/05/2023] Open
Abstract
l-asparaginase (EC 3.5.1.1) is an enzyme that catalysis mainly the asparagine hydrolysis in l-aspartic acid and ammonium. This enzyme is presented in different organisms, such as microorganisms, vegetal, and some animals, including certain rodent's serum, but not unveiled in humans. It can be used as important chemotherapeutic agent for the treatment of a variety of lymphoproliferative disorders and lymphomas (particularly acute lymphoblastic leukemia (ALL) and Hodgkin's lymphoma), and has been a pivotal agent in chemotherapy protocols from around 30 years. Also, other important application is in food industry, by using the properties of this enzyme to reduce acrylamide levels in commercial fried foods, maintaining their characteristics (color, flavor, texture, security, etc.) Actually, l-asparaginase catalyzes the hydrolysis of l-asparagine, not allowing the reaction of reducing sugars with this aminoacid for the generation of acrylamide. Currently, production of l-asparaginase is mainly based in biotechnological production by using some bacteria. However, industrial production also needs research work aiming to obtain better production yields, as well as novel process by applying different microorganisms to increase the range of applications of the produced enzyme. Within this context, this mini-review presents l-asparaginase applications, production by different microorganisms and some limitations, current investigations, as well as some challenges to be achieved for profitable industrial production.
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Mu Y, Wan X, Lin K, Ao J, Chen X. Liver proteomic analysis of the large yellow croaker (Pseudosciaena crocea) following polyriboinosinic:polyribocytidylic acid induction. FISH PHYSIOLOGY AND BIOCHEMISTRY 2013; 39:1267-1276. [PMID: 23479204 DOI: 10.1007/s10695-013-9781-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2012] [Accepted: 03/02/2013] [Indexed: 06/01/2023]
Abstract
In the present study, we examined the liver protein profiles of the large yellow croaker (Pseudosciaena crocea) exposed to polyriboinosinic:polyribocytidylic acid [poly(I:C)], a viral mimic, using the differential proteomic approach. Sixteen altered protein spots were identified by matrix-assisted laser desorption ionization time of flight mass spectrometry or matrix-assisted laser desorption ionization time of flight/time of flight mass spectrometry, including eight upregulated proteins and eight downregulated proteins. These altered host proteins were classified into six categories based on their biological function: cellular process, metabolic process, biological regulation, binding, and catabolic process, highlighting the fact that response to poly(I:C) induction in fish seems to be complex and diverse. Moreover, four corresponding genes of the differentially expressed proteins were validated by relative quantitative real-time PCR. Western blot analysis further demonstrated the changes in protein abundance of natural killer enhancing factor and peroxiredoxin 6. These results will be helpful in furthering our understanding of the changes of physiological processes in liver of fish during virus infection.
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Affiliation(s)
- Yinnan Mu
- Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography, State Oceanic Administration, Xiamen, 361005, People's Republic of China
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Mulenga A, Erikson K. A snapshot of the Ixodes scapularis degradome. Gene 2011; 482:78-93. [PMID: 21596113 DOI: 10.1016/j.gene.2011.04.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Revised: 03/04/2011] [Accepted: 04/15/2011] [Indexed: 01/19/2023]
Abstract
Parasitic encoded proteases are essential to regulating interactions between parasites and their hosts and thus they represent attractive anti-parasitic druggable and/or vaccine target. We have utilized annotations of Ixodes scapularis proteases in gene bank and version 9.3 MEROPS database to compile an index of at least 233 putatively active and 150 putatively inactive protease enzymes that are encoded by the I. scapularis genome. The 233 putatively active protease homologs hereafter referred to as the degradome (the full repertoire of proteases encoded by the I. scapularis genome) represent ~1.14% of the 20485 putative I. scapularis protein content. Consistent with observations in other animals, the content of the I. scapularis degradome is ~6.0% (14/233) aspartic, ~19% (44/233) cysteine, ~40% (93/233) metallo, ~28.3% (66/233) serine and ~6.4% (15/233) threonine proteases. When scanned against other tick sequences, ~11% (25/233) of I. scapularis putatively active proteases are conserved in other tick species with ≥ 60% amino acid identity levels. The I. scapularis genome does not apparently encode for putatively inactive aspartic proteases. Of the 150 putative inactive protease homologs none are from the aspartic protease class, ~8% (12/150) are cysteine, ~58.7% (88/150) metallo, 30% (45/150) serine and ~3.3% (5/150) are threonine proteases. The I. scapularis tick genome appears to have evolutionarily lost proteolytic activity of at least 6 protease families, C56 and C64 (cysteine), M20 and M23 (metallo), S24 and S28 (serine) as revealed by a lack of the putatively active proteases in these families. The overall protease content is comparable to other organisms. However, the paucity of the S1 chymotrypsin/trypsin-like serine protease family in the I. scapularis genome where it is ~12.7% (28/233) of the degradome as opposed to ~22-48% content in other blood feeding arthropods, Pediculus humanus humanus, Anopheles gambiae, Aedes Aegypti and Culex pipiens quinquefasciatus is notable. The data is presented as a one-stop index of proteases encoded by the I. scapularis genome.
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Affiliation(s)
- Albert Mulenga
- Texas A & M University AgriLife Research, Department of Entomology, College Station, TX 77843, USA.
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Cantor JR, Stone EM, Chantranupong L, Georgiou G. The human asparaginase-like protein 1 hASRGL1 is an Ntn hydrolase with beta-aspartyl peptidase activity. Biochemistry 2009; 48:11026-31. [PMID: 19839645 PMCID: PMC2782781 DOI: 10.1021/bi901397h] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Herein we report the bacterial expression, purification, and enzymatic characterization of the human asparaginase-like protein 1 (hASRGL1). We present evidence that hASRGL1 exhibits beta-aspartyl peptidase activity consistent with enzymes designated as plant-type asparaginases, which had thus far been found in only plants and bacteria. Similar to nonmammalian plant-type asparaginases, hASRGL1 is shown to be an Ntn hydrolase for which Thr168 serves as the essential N-terminal nucleophile for intramolecular processing and catalysis, corroborated in part by abolishment of both activities through the Thr168Ala point mutation. In light of the activity profile reported here, ASRGL1s may act synergistically with protein l-isoaspartyl methyl transferase to relieve accumulation of potentially toxic isoaspartyl peptides in mammalian brain and other tissues.
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Affiliation(s)
- Jason R. Cantor
- Department of Chemical Engineering, University of Texas, Austin, Texas 78712, USA
| | - Everett M. Stone
- Department of Chemical Engineering, University of Texas, Austin, Texas 78712, USA
| | | | - George Georgiou
- Department of Chemical Engineering, University of Texas, Austin, Texas 78712, USA
- Institute for Cell and Molecular Biology, University of Texas, Austin, Texas 78712, USA
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Kelo E, Noronkoski T, Mononen I. Depletion of L-asparagine supply and apoptosis of leukemia cells induced by human glycosylasparaginase. Leukemia 2009; 23:1167-71. [DOI: 10.1038/leu.2008.387] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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12
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Borek D, Michalska K, Brzezinski K, Kisiel A, Podkowinski J, Bonthron DT, Krowarsch D, Otlewski J, Jaskolski M. Expression, purification and catalytic activity of Lupinus luteus asparagine β-amidohydrolase and its Escherichia coli homolog. ACTA ACUST UNITED AC 2004; 271:3215-26. [PMID: 15265041 DOI: 10.1111/j.1432-1033.2004.04254.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We describe the expression, purification, and biochemical characterization of two homologous enzymes, with amidohydrolase activities, of plant (Lupinus luteus potassium-independent asparaginase, LlA) and bacterial (Escherichia coli, ybiK/spt/iaaA gene product, EcAIII) origin. Both enzymes were expressed in E. coli cells, with (LlA) or without (EcAIII) a His-tag sequence. The proteins were purified, yielding 6 or 30 mg.L(-1) of culture, respectively. The enzymes are heat-stable up to 60 degrees C and show both isoaspartyl dipeptidase and l-asparaginase activities. Kinetic parameters for both enzymatic reactions have been determined, showing that the isoaspartyl peptidase activity is the dominating one. Despite sequence similarity to aspartylglucosaminidases, no aspartylglucosaminidase activity could be detected. Phylogenetic analysis demonstrated the relationship of these proteins to other asparaginases and aspartylglucosaminidases and suggested their classification as N-terminal nucleophile hydrolases. This is consistent with the observed autocatalytic breakdown of the immature proteins into two subunits, with liberation of an N-terminal threonine as a potential catalytic residue.
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Affiliation(s)
- Dominika Borek
- Department of Crystallography, Faculty of Chemistry, A. Mickiewicz University, Poznan, Poland
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Kelo E, Noronkoski T, Stoineva IB, Petkov DD, Mononen I. β-Aspartylpeptides as substrates ofL-asparaginases fromEscherichia coliandErwinia chrysanthemi. FEBS Lett 2002; 528:130-2. [PMID: 12297292 DOI: 10.1016/s0014-5793(02)03273-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
L-Asparaginase is known to catalyze the hydrolysis of L-asparagine to L-aspartic and ammonia, but little is known about its action on peptides. When we incubated L-asparaginases purified either from Escherichia coli or Erwinia chrysanthemi - commonly used as chemotherapeutic agents because of their antitumour activity - with eight small beta-aspartylpeptides such as beta-aspartylserineamide, beta-aspartylalanineamide, beta-aspartylglycineamide and beta-aspartylglycine, we found that both L-asparaginases could catalyze the hydrolysis of five of them yielding L-aspartic acid and amino acids or peptides. Our data show that L-asparaginases can hydrolyze beta-aspartylpeptides and suggest that L-asparaginase therapy may affect the metabolism of beta-aspartylpeptides present in human body.
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Affiliation(s)
- Eira Kelo
- Department of Clinical Chemistry, Kuopio University Hospital, Finland.
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Hejazi M, Piotukh K, Mattow J, Deutzmann R, Volkmer-Engert R, Lockau W. Isoaspartyl dipeptidase activity of plant-type asparaginases. Biochem J 2002; 364:129-36. [PMID: 11988085 PMCID: PMC1222554 DOI: 10.1042/bj3640129] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Recombinant plant-type asparaginases from the cyanobacteria Synechocystis sp. PCC (Pasteur culture collection) 6803 and Anabaena sp. PCC 7120, from Escherichia coli and from the plant Arabidopsis thaliana were expressed in E. coli with either an N-terminal or a C-terminal His tag, and purified. Although each of the four enzymes is encoded by a single gene, their mature forms consist of two protein subunits that are generated by autoproteolytic cleavage of the primary translation products at the Gly-Thr bond within the sequence GTI/VG. The enzymes not only deamidated asparagine but also hydrolysed a range of isoaspartyl dipeptides. As various isoaspartyl peptides are known to arise from proteolytic degradation of post-translationally altered proteins containing isoaspartyl residues, and from depolymerization of the cyanobacterial reserve polymer multi-L-arginyl-poly-L-aspartic acid (cyanophycin), plant-type asparaginases may not only function in asparagine catabolism but also in the final steps of protein and cyanophycin degradation. The properties of these enzymes are compared with those of the sequence-related glycosylasparaginases.
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Affiliation(s)
- Mahdi Hejazi
- Institut für Biologie, Humboldt-Universität zu Berlin, Chausseestr. 117, D-10115 Berlin, Germany
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15
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Risley JM, Huang DH, Kaylor JJ, Malik JJ, Xia YQ, York WM. Glycosylasparaginase activity requires the alpha-carboxyl group, but not the alpha-amino group, on N(4)-(2-Acetamido-2-deoxy-beta-D-glucopyranosyl)-L-asparagine. Arch Biochem Biophys 2001; 391:165-70. [PMID: 11437347 DOI: 10.1006/abbi.2001.2416] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Glycosylasparaginase catalyzes the hydrolysis of the N-glycosylic bond in N(4)-(2-acetamido-2-deoxy-beta-D-glucopyranosyl)-L-asparagine in the catabolism of N-linked oligosaccharides. A deficiency, or absence, of enzyme activity gives rise to aspartylglycosaminuria, the most common disorder of glycoprotein metabolism. The enzyme catalyzes the hydrolysis of a variety of asparagine and aspartyl compounds containing a free alpha-carboxyl group and a free alpha-amino group; computational studies suggest that the alpha-amino group actively participates in the catalytic mechanism. In order to study the importance of the alpha-carboxyl group and the alpha-amino group on the natural substrate to the reaction catalyzed by the enzyme, 14 analogues of the natural substrate were studied where the structure of the aspartyl group of the substrate was changed. The incremental binding energy (DeltaDeltaGb) for those analogues that were substrates was calculated. The results show that the alpha-amino group may be substituted with a group of comparable size, for the alpha-amino group contributes little, if any, to the transition state binding energy of the natural substrate. The alpha-amino group position acts as an "anchor" in the binding site for the substrate. On the other hand, the alpha-carboxyl group is necessary for enzyme activity; removal of the alpha-carboxyl group or changing it to an alpha-carboxamide group results in no hydrolysis reaction. Also, N-acetyl-D-glucosamine is not sufficient for binding to the active site for efficient hydrolysis by the enzyme. These results provide supporting evidence for a proposed intramolecular autoproteolytic activation reaction for the enzyme. However, the results raise a question as to an important role for the alpha-amino group in the catalytic mechanism as indicated in computational studies.
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Affiliation(s)
- J M Risley
- Department of Chemistry, The University of North Carolina at Charlotte, Charlotte, North Carolina 28223, USA.
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Larsen RA, Knox TM, Miller CG. Aspartic peptide hydrolases in Salmonella enterica serovar typhimurium. J Bacteriol 2001; 183:3089-97. [PMID: 11325937 PMCID: PMC95209 DOI: 10.1128/jb.183.10.3089-3097.2001] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Two well-characterized enzymes in Salmonella enterica serovar Typhimurium and Escherichia coli are able to hydrolyze N-terminal aspartyl (Asp) dipeptides: peptidase B, a broad-specificity aminopeptidase, and peptidase E, an Asp-specific dipeptidase. A serovar Typhimurium strain lacking both of these enzymes, however, can still utilize most N-terminal Asp dipeptides as sources of amino acids, and extracts of such a strain contain additional enzymatic activities able to hydrolyze Asp dipeptides. Here we report two such activities from extracts of pepB pepE mutant strains of serovar Typhimurium identified by their ability to hydrolyze Asp-Leu. Although each of these activities hydrolyzes Asp-Leu at a measurable rate, the preferred substrates for both are N-terminal isoAsp peptides. One of the activities is a previously characterized isoAsp dipeptidase from E. coli, the product of the iadA gene. The other is the product of the serovar Typhimurium homolog of E. coli ybiK, a gene of previously unknown function. This gene product is a member of the N-terminal nucleophile structural family of amidohydrolases. Like most other members of this family, the mature enzyme is generated from a precursor protein by proteolytic cleavage and the active enzyme is a heterotetramer. Based on its ability to hydrolyze an N-terminal isoAsp tripeptide as well as isoAsp dipeptides, the enzyme appears to be an isoAsp aminopeptidase, and we propose that the gene encoding it be designated iaaA (isoAsp aminopeptidase). A strain lacking both IadA and IaaA in addition to peptidase B and peptidase E has been constructed. This strain utilizes Asp-Leu as a leucine source, and extracts of this strain contain at least one additional, as-yet-uncharacterized, peptidase able to cleave Asp dipeptides.
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Affiliation(s)
- R A Larsen
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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Aronson NN. Aspartylglycosaminuria: biochemistry and molecular biology. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1455:139-54. [PMID: 10571008 DOI: 10.1016/s0925-4439(99)00076-9] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Aspartylglucosaminuria (AGU, McKusick 208400) is an autosomal recessive lysosomal storage disease caused by defective degradation of Asn-linked glycoproteins. AGU mutations occur in the gene (AGA) for glycosylasparaginase, the enzyme necessary for hydrolysis of the protein oligosaccharide linkage in Asn-linked glycoprotein substrates undergoing metabolic turnover. Loss of glycosylasparaginase activity leads to accumulation of the linkage unit Asn-GlcNAc in tissue lysosomes. Storage of this fragment affects the pathophysiology of neuronal cells most severely. The patients notably suffer from decreased cognitive abilities, skeletal abnormalities and facial grotesqueness. The progress of the disease is slower than in many other lysosomal storage diseases. The patients appear normal during infancy and generally live from 25 to 45 years. A specific AGU mutation is concentrated in the Finnish population with over 200 patients. The carrier frequency in Finland has been estimated to be in the range of 2.5-3% of the population. So far there are 20 other rare family AGU alleles that have been characterized at the molecular level in the world's population. Recently, two knockout mouse models for AGU have been developed. In addition, the crystal structure of human leukocyte glycosylasparaginase has been determined and the protein has a unique alphabetabetaalpha sandwich fold shared by a newly recognized family of important enzymes called N-terminal nucleophile (Ntn) hydrolases. The nascent single-chain precursor of glycosylase araginase self-cleaves into its mature alpha- and beta-subunits, a reaction required to activate the enzyme. This interesting biochemical feature is also shared by most of the Ntn-hydrolase family of proteins. Many of the disease-causing mutations prevent proper folding and subsequent activation of the glycosylasparaginase.
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Affiliation(s)
- N N Aronson
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile 36688-0002, USA.
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