1
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Zhang D, Czapinska H, Bochtler M, Wlodawer A, Lubkowski J. RrA, an enzyme from Rhodospirillum rubrum, is a prototype of a new family of short-chain L-asparaginases. Protein Sci 2024; 33:e4920. [PMID: 38501449 PMCID: PMC10949315 DOI: 10.1002/pro.4920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 01/22/2024] [Accepted: 01/26/2024] [Indexed: 03/20/2024]
Abstract
L-Asparaginases (ASNases) catalyze the hydrolysis of L-Asn to L-Asp and ammonia. Members of the ASNase family are used as drugs in the treatment of leukemia, as well as in the food industry. The protomers of bacterial ASNases typically contain 300-400 amino acids (typical class 1 ASNases). In contrast, the chain of ASNase from Rhodospirillum rubrum, reported here and referred to as RrA, consists of only 172 amino acid residues. RrA is homologous to the N-terminal domain of typical bacterial class 1 ASNases and exhibits millimolar affinity for L-Asn. In this study, we demonstrate that RrA belongs to a unique family of cytoplasmic, short-chain ASNases (scASNases). These proteins occupy a distinct region in the sequence space, separate from the regions typically assigned to class 1 ASNases. The scASNases are present in approximately 7% of eubacterial species, spanning diverse bacterial lineages. They seem to be significantly enriched in species that encode for more than one class 1 ASNase. Here, we report biochemical, biophysical, and structural properties of RrA, a member of scASNases family. Crystal structures of the wild-type RrA, both with and without bound L-Asp, as well as structures of several RrA mutants, reveal topologically unique tetramers. Moreover, the active site of one protomer is complemented by two residues (Tyr21 and Asn26) from another protomer. Upon closer inspection, these findings clearly outline scASNases as a stand-alone subfamily of ASNases that can catalyze the hydrolysis of L-Asn to L-Asp despite the lack of the C-terminal domain that is present in all ASNases described structurally to date.
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Affiliation(s)
- Di Zhang
- Center for Structural BiologyNational Cancer InstituteFrederickMarylandUSA
| | - Honorata Czapinska
- Laboratory of Structural BiologyInternational Institute of Molecular and Cell BiologyWarsawPoland
- Institute of Biochemistry and BiophysicsPolish Academy of SciencesWarsawPoland
| | - Matthias Bochtler
- Laboratory of Structural BiologyInternational Institute of Molecular and Cell BiologyWarsawPoland
- Institute of Biochemistry and BiophysicsPolish Academy of SciencesWarsawPoland
| | - Alexander Wlodawer
- Center for Structural BiologyNational Cancer InstituteFrederickMarylandUSA
| | - Jacek Lubkowski
- Center for Structural BiologyNational Cancer InstituteFrederickMarylandUSA
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2
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Strzelczyk P, Zhang D, Alexandratos J, Piszczek G, Wlodawer A, Lubkowski J. The dimeric form of bacterial l-asparaginase YpAI is fully active. FEBS J 2023; 290:780-795. [PMID: 36152020 PMCID: PMC10683579 DOI: 10.1111/febs.16635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 09/05/2022] [Accepted: 09/23/2022] [Indexed: 02/04/2023]
Abstract
l-asparaginases from mesophilic bacteria (ASNases), including two enzymes very successfully used in the treatment of leukaemia, have been consistently described as homotetramers. On the contrary, structural studies show that homodimers of these enzymes should be sufficient to carry out the catalytic reaction. In this report, we investigated whether the type I Yersinia pestis asparaginase (YpAI) is active in a dimeric form or whether the tetrameric quaternary structure is critical for its activity. Using multiple biophysical techniques that investigate enzymatic properties and quaternary structure at either high or low protein concentration, we found that dimeric YpAI is fully active, suggesting that the tetrameric form of this subfamily of enzymes does not bear significant enzymatic relevance. In this process, we extensively characterized YpAI, showing that it is a cooperative enzyme, although the mechanism of allostery is still not definitely established. We showed that, like most type I ASNases, the substrate affinity of YpAI is low and this enzyme is very similar in terms of both the structure and enzymatic properties to homologous type I ASNase from Escherichia coli (EcAI). We extended these studies to more medically relevant type II ASNases, used as anti-leukaemia drugs. We confirmed that type II ASNases are not allosteric, and that they might also be functional in a dimeric form. However, the determination of the accurate tetramer⇆dimer dissociation constants of these enzymes that most likely lie in the picomolar range is not possible with currently available biophysical techniques.
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Affiliation(s)
- Pawel Strzelczyk
- Center for Structural Biology, Center for Cancer Research, National Cancer Institute, Frederick, MD, USA
| | - Di Zhang
- Center for Structural Biology, Center for Cancer Research, National Cancer Institute, Frederick, MD, USA
| | - Jerry Alexandratos
- Center for Structural Biology, Center for Cancer Research, National Cancer Institute, Frederick, MD, USA
| | - Grzegorz Piszczek
- Biophysics Core Facility, National Heart, Lung, and Blood Institute, Bethesda, MD, USA
| | - Alexander Wlodawer
- Center for Structural Biology, Center for Cancer Research, National Cancer Institute, Frederick, MD, USA
| | - Jacek Lubkowski
- Center for Structural Biology, Center for Cancer Research, National Cancer Institute, Frederick, MD, USA
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3
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Strzelczyk P, Zhang D, Wlodawer A, Lubkowski J. The E. coli L-asparaginase V27T mutant: structural and functional characterization and comparison with theoretical predictions. FEBS Lett 2022; 596:3060-3068. [PMID: 36310372 PMCID: PMC10673687 DOI: 10.1002/1873-3468.14526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 10/18/2022] [Accepted: 10/20/2022] [Indexed: 01/14/2023]
Abstract
Bacterial L-asparaginases have been used for over 40 years as anticancer drugs. Ardalan et al. (Medical Hypotheses 112, 7-17, 2018) proposed that the V27T mutant of Escherichia coli type II L-asparaginase, EcAII(V27T), should display altered biophysical and catalytic properties compared to the wild-type enzyme, EcAII(wt), rendering it more favourable as a pharmaceutical. They postulated that EcAII(V27T) would exhibit reduced glutaminolytic activity and be more stable compared to EcAII(wt). Their postulates, however, were purely theoretical. Here, we characterized experimentally selected properties of EcAII(V27T). We found asparaginolytic activity of this mutant unchanged, whereas its glutaminolytic activity was fourfold lower compared with EcAII(wt). We did not observe significant differences in stabilities of EcAII(wt) and EcAII(V27T). Crystal structures of the complexes with L-Asp and L-Glu showed considerable differences in binding modes of both substrates.
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Affiliation(s)
- Pawel Strzelczyk
- Center for Structural Biology, Center for Cancer Research, National Cancer Institute, Frederick, MD, USA
| | - Di Zhang
- Center for Structural Biology, Center for Cancer Research, National Cancer Institute, Frederick, MD, USA
| | - Alexander Wlodawer
- Center for Structural Biology, Center for Cancer Research, National Cancer Institute, Frederick, MD, USA
| | - Jacek Lubkowski
- Center for Structural Biology, Center for Cancer Research, National Cancer Institute, Frederick, MD, USA
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4
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Safrhansova L, Hlozkova K, Starkova J. Targeting amino acid metabolism in cancer. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2022; 373:37-79. [PMID: 36283767 DOI: 10.1016/bs.ircmb.2022.08.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Metabolic rewiring is a characteristic hallmark of cancer cells. This phenomenon sustains uncontrolled proliferation and resistance to apoptosis by increasing nutrients and energy supply. However, reprogramming comes together with vulnerabilities that can be used against tumor and can be applied in targeted therapy. In the last years, the genetic background of tumors has been identified thoroughly and new therapies targeting those mutations tested. Nevertheless, we propose that targeting the phenotype of cancer cells could be another way of treatment aiming to avoid drug resistance and non-responsiveness of cancer patients. Amino acid metabolism is part of the altered processes in cancer cells. Amino acids are building blocks and also sensors of signaling pathways regulating main biological processes. In this comprehensive review, we described four amino acids (asparagine, arginine, methionine, and cysteine) which have been actively investigated as potential targets for anti-tumor therapy. Asparagine depletion is successfully used for decades in the treatment of acute lymphoblastic leukemia and there is a strong implication to apply it to other types of tumors. Arginine auxotrophic tumors are great candidates for arginine-starvation therapy. Higher requirement for essential amino acids such as methionine and cysteine point out promising targetable weaknesses of cancer cells.
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Affiliation(s)
- Lucie Safrhansova
- CLIP - Childhood Leukaemia Investigation Prague, Prague, Czech Republic; Dept. of Pediatric Hematology and Oncology, Second Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Katerina Hlozkova
- CLIP - Childhood Leukaemia Investigation Prague, Prague, Czech Republic; Dept. of Pediatric Hematology and Oncology, Second Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Julia Starkova
- CLIP - Childhood Leukaemia Investigation Prague, Prague, Czech Republic; Dept. of Pediatric Hematology and Oncology, Second Faculty of Medicine, Charles University, Prague, Czech Republic; University Hospital Motol, Prague, Czech Republic.
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5
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Pokrovskaya MV, Pokrovsky VS, Aleksandrova SS, Sokolov NN, Zhdanov DD. Molecular Analysis of L-Asparaginases for Clarification of the Mechanism of Action and Optimization of Pharmacological Functions. Pharmaceutics 2022; 14:pharmaceutics14030599. [PMID: 35335974 PMCID: PMC8948990 DOI: 10.3390/pharmaceutics14030599] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 02/24/2022] [Accepted: 03/07/2022] [Indexed: 12/19/2022] Open
Abstract
L-asparaginases (EC 3.5.1.1) are a family of enzymes that catalyze the hydrolysis of L-asparagine to L-aspartic acid and ammonia. These proteins with different biochemical, physicochemical and pharmacological properties are found in many organisms, including bacteria, fungi, algae, plants and mammals. To date, asparaginases from E. coli and Dickeya dadantii (formerly known as Erwinia chrysanthemi) are widely used in hematology for the treatment of lymphoblastic leukemias. However, their medical use is limited by side effects associated with the ability of these enzymes to hydrolyze L-glutamine, as well as the development of immune reactions. To solve these issues, gene-editing methods to introduce amino-acid substitutions of the enzyme are implemented. In this review, we focused on molecular analysis of the mechanism of enzyme action and to optimize the antitumor activity.
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Affiliation(s)
- Marina V. Pokrovskaya
- Institute of Biomedical Chemistry, Pogodinskaya Str. 10/8, 119121 Moscow, Russia; (M.V.P.); (S.S.A.); (N.N.S.)
| | - Vadim S. Pokrovsky
- Department of Biochemistry, Peoples’ Friendship University of Russia (RUDN University), Miklukho-Maklaya Str. 6, 117198 Moscow, Russia;
- Laboratory of Combined Treatment, N.N. Blokhin Cancer Research Center, Kashirskoe Shosse 24, 115478 Moscow, Russia
- Center of Genetics and Life Sciences, Sirius University of Science and Technology, Federal Territory Sirius, Olimpiisky Prospect 1, 354340 Sochi, Russia
| | - Svetlana S. Aleksandrova
- Institute of Biomedical Chemistry, Pogodinskaya Str. 10/8, 119121 Moscow, Russia; (M.V.P.); (S.S.A.); (N.N.S.)
| | - Nikolay N. Sokolov
- Institute of Biomedical Chemistry, Pogodinskaya Str. 10/8, 119121 Moscow, Russia; (M.V.P.); (S.S.A.); (N.N.S.)
| | - Dmitry D. Zhdanov
- Institute of Biomedical Chemistry, Pogodinskaya Str. 10/8, 119121 Moscow, Russia; (M.V.P.); (S.S.A.); (N.N.S.)
- Department of Biochemistry, Peoples’ Friendship University of Russia (RUDN University), Miklukho-Maklaya Str. 6, 117198 Moscow, Russia;
- Correspondence:
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6
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Lubkowski J, Wlodawer A. Structural and biochemical properties of L-asparaginase. FEBS J 2021; 288:4183-4209. [PMID: 34060231 DOI: 10.1111/febs.16042] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 05/24/2021] [Accepted: 05/28/2021] [Indexed: 12/22/2022]
Abstract
l-Asparaginase (a hydrolase converting l-asparagine to l-aspartic acid) was the first enzyme to be used in clinical practice as an anticancer agent after its approval in 1978 as a component of a treatment protocol for childhood acute lymphoblastic leukemia. Structural and biochemical properties of l-asparaginases have been extensively investigated during the last half-century, providing an accurate structural description of the enzyme isolated from a variety of sources, as well as clarifying the mechanism of its activity. This review provides a critical assessment of the current state of knowledge of primarily structural, but also selected biochemical properties of 'bacterial-type' l-asparaginases from different organisms. The most extensively studied members of this enzyme family are l-asparaginases highly homologous to one of the two enzymes from Escherichia coli (usually referred to as EcAI and EcAII). Members of this enzyme family, although often called bacterial-type l-asparaginases, have been also identified in such divergent organisms as archaea or eukarya. Over 100 structural models of l-asparaginases have been deposited in the Protein Data Bank during the last 30 years. One of the prime achievements of structure-centered approaches was the elucidation of the details of the mechanism of enzymatic action of this unique hydrolase that utilizes a side chain of threonine as the primary nucleophile. The molecular basis of other important properties of these enzymes, such as their substrate specificity, is still being evaluated. Results of structural and mechanistic studies of l-asparaginases are being utilized in efforts to improve the clinical properties of this important anticancer drug.
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Affiliation(s)
- Jacek Lubkowski
- Center for Structural Biology, Center for Cancer Research, National Cancer Institute, Frederick, MD, USA
| | - Alexander Wlodawer
- Center for Structural Biology, Center for Cancer Research, National Cancer Institute, Frederick, MD, USA
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7
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Strzelczyk P, Zhang D, Dyba M, Wlodawer A, Lubkowski J. Generalized enzymatic mechanism of catalysis by tetrameric L-asparaginases from mesophilic bacteria. Sci Rep 2020; 10:17516. [PMID: 33060684 PMCID: PMC7567106 DOI: 10.1038/s41598-020-74480-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 09/24/2020] [Indexed: 11/09/2022] Open
Abstract
The mechanism of catalysis by the L-glutaminase-asparaginase from Pseudomonas 7A (PGA) was investigated using structural, mass spectrometry, and kinetic data. We had previously proposed mechanism of hydrolysis of L-Asn by the type II L-asparaginase from E. coli (EcAII), but that work was limited to just one enzyme. Based on results presented in this report, we postulate that all homotetrameric L-asparaginases from mesophilic bacteria utilize a common ping-pong mechanism of catalysis consisting of two subsequent nucleophilic substitutions. Several new structures of non-covalent complexes of PGA with different substrates, as well as structures of covalent acyl-enzyme intermediates of PGA with canonical substrates (L-Asp and L-Glu) and an opportunistic ligand, a citrate anion, were determined. The results of kinetic experiments monitored by high-resolution LC/MS, when combined with new structural data, clearly show that the reaction catalyzed by L-glutaminase-asparaginases proceeds through formation of a covalent intermediate, as observed previously for EcAII. Additionally, by showing that the same mechanism applies to L-Asn and L-Gln, we postulate that it is common for all these structurally related enzymes.
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Affiliation(s)
- Pawel Strzelczyk
- Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, MD, USA
| | - Di Zhang
- Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, MD, USA
| | - Marzena Dyba
- Basic Science Program, Structural Biophysics Laboratory, Frederick National Laboratory for Cancer Research Sponsored by the National Cancer Institute, Frederick, MD, USA
| | - Alexander Wlodawer
- Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, MD, USA
| | - Jacek Lubkowski
- Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, MD, USA.
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8
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Radadiya A, Zhu W, Coricello A, Alcaro S, Richards NGJ. Improving the Treatment of Acute Lymphoblastic Leukemia. Biochemistry 2020; 59:3193-3200. [PMID: 32786406 PMCID: PMC7497903 DOI: 10.1021/acs.biochem.0c00354] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
l-Asparaginase (EC 3.5.1.1) was first used as a component of combination drug therapies to treat acute lymphoblastic leukemia (ALL), a cancer of the blood and bone marrow, almost 50 years ago. Administering this enzyme to reduce asparagine levels in the blood is a cornerstone of modern clinical protocols for ALL; indeed, this remains the only successful example of a therapy targeted against a specific metabolic weakness in any form of cancer. Three problems, however, constrain the clinical use of l-asparaginase. First, a type II bacterial variant of l-asparaginase is administered to patients, the majority of whom are children, which produces an immune response thereby limiting the time over which the enzyme can be tolerated. Second, l-asparaginase is subject to proteolytic degradation in the blood. Third, toxic side effects are observed, which may be correlated with the l-glutaminase activity of the enzyme. This Perspective will outline how asparagine depletion negatively impacts the growth of leukemic blasts, discuss the structure and mechanism of l-asparaginase, and briefly describe the clinical use of chemically modified forms of clinically useful l-asparaginases, such as Asparlas, which was recently given FDA approval for use in children (babies to young adults) as part of multidrug treatments for ALL. Finally, we review ongoing efforts to engineer l-asparaginase variants with improved therapeutic properties and briefly detail emerging, alternate strategies for the treatment of forms of ALL that are resistant to asparagine depletion.
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Affiliation(s)
- Ashish Radadiya
- School of Chemistry, Cardiff University, Park Place, Cardiff CF10 3AT, U.K
| | - Wen Zhu
- Department of Chemistry and California Institute for Quantitative Biosciences, University of California, Berkeley, California 94720, United States
| | - Adriana Coricello
- School of Chemistry, Cardiff University, Park Place, Cardiff CF10 3AT, U.K.,Dipartimento di Scienze della Salute, Università "Magna Græcia" di Catanzaro, 88100 Catanzaro, Italy
| | - Stefano Alcaro
- Dipartimento di Scienze della Salute, Università "Magna Græcia" di Catanzaro, 88100 Catanzaro, Italy.,Net4Science, Università "Magna Græcia" di Catanzaro, 88100 Catanzaro, Italy
| | - Nigel G J Richards
- School of Chemistry, Cardiff University, Park Place, Cardiff CF10 3AT, U.K.,Foundation for Applied Molecular Evolution, 13079 Progress Boulevard, Alachua, Florida 32615, United States
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9
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Timofeev VI, Zhukhlistova NE, Kuranova IP. Molecular Packing of a Mutant of L-Asparaginase from Wolinella succinigenes in Two Crystal Modifications. CRYSTALLOGR REP+ 2020. [DOI: 10.1134/s1063774520040227] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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10
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Lubkowski J, Vanegas J, Chan WK, Lorenzi PL, Weinstein JN, Sukharev S, Fushman D, Rempe S, Anishkin A, Wlodawer A. Mechanism of Catalysis by l-Asparaginase. Biochemistry 2020; 59:1927-1945. [PMID: 32364696 DOI: 10.1021/acs.biochem.0c00116] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Two bacterial type II l-asparaginases, from Escherichia coli and Dickeya chrysanthemi, have played a critical role for more than 40 years as therapeutic agents against juvenile leukemias and lymphomas. Despite a long history of successful pharmacological applications and the apparent simplicity of the catalytic reaction, controversies still exist regarding major steps of the mechanism. In this report, we provide a detailed description of the reaction catalyzed by E. coli type II l-asparaginase (EcAII). Our model was developed on the basis of new structural and biochemical experiments combined with previously published data. The proposed mechanism is supported by quantum chemistry calculations based on density functional theory. We provide strong evidence that EcAII catalyzes the reaction according to the double-displacement (ping-pong) mechanism, with formation of a covalent intermediate. Several steps of catalysis by EcAII are unique when compared to reactions catalyzed by other known hydrolytic enzymes. Here, the reaction is initiated by a weak nucleophile, threonine, without direct assistance of a general base, although a distant general base is identified. Furthermore, tetrahedral intermediates formed during the catalytic process are stabilized by a never previously described motif. Although the scheme of the catalytic mechanism was developed only on the basis of data obtained from EcAII and its variants, this novel mechanism of enzymatic hydrolysis could potentially apply to most (and possibly all) l-asparaginases.
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Affiliation(s)
- Jacek Lubkowski
- Macromolecular Crystallography Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702, United States
| | - Juan Vanegas
- Department of Physics, The University of Vermont, Burlington, Vermont 05408, United States
| | - Wai-Kin Chan
- Department of Bioinformatics and Computational Biology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, United States
| | - Philip L Lorenzi
- Department of Bioinformatics and Computational Biology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, United States
| | - John N Weinstein
- Department of Bioinformatics and Computational Biology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, United States
| | - Sergei Sukharev
- Department of Biology, University of Maryland, College Park, Maryland 20742, United States
| | - David Fushman
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States
| | - Susan Rempe
- Center for Biological and Engineering Sciences, Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
| | - Andriy Anishkin
- Department of Biology, University of Maryland, College Park, Maryland 20742, United States
| | - Alexander Wlodawer
- Macromolecular Crystallography Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702, United States
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11
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Timofeev VI, Zhukhlistova NE, Kuranova IP. Features of the Three Dimensional Structure of the Mutant Form of Wolinella succinogenes L-Asparaginase in Complexes with L-Aspartic and L-Glutamic Acids. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2020. [DOI: 10.1134/s1068162020020168] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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12
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Timofeev VI, Bulushova NV, Zhukhlistova NE, Kuranova IP. Crystallization and Preliminary X-ray Diffraction Study of a Mutant of L-Asparaginase from Wolinella succinogenes. CRYSTALLOGR REP+ 2019. [DOI: 10.1134/s1063774519060221] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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13
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Lubkowski J, Wlodawer A. Geometric considerations support the double-displacement catalytic mechanism of l-asparaginase. Protein Sci 2019; 28:1850-1864. [PMID: 31423681 PMCID: PMC6740147 DOI: 10.1002/pro.3709] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 08/13/2019] [Accepted: 08/13/2019] [Indexed: 11/09/2022]
Abstract
Twenty crystal structures of the complexes of l-asparaginase with l-Asn, l-Asp, and succinic acid that are currently available in the Protein Data Bank, as well as 11 additional structures determined in the course of this project, were analyzed in order to establish the level of conservation of the geometric parameters describing interactions between the substrates and the active site of the enzymes. We found that such stereochemical relationships are highly conserved, regardless of the organism from which the enzyme was isolated, specific crystallization conditions, or the nature of the ligands. Analysis of the geometry of the interactions, including Bürgi-Dunitz and Flippin-Lodge angles, indicated that Thr12 (Escherichia coli asparaginase II numbering) is optimally placed to be the primary nucleophile in the most likely scenario utilizing a double-displacement mechanism, whereas catalysis through a single-displacement mechanism appears to be the least likely.
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Affiliation(s)
- Jacek Lubkowski
- Macromolecular Crystallography LaboratoryNational Cancer InstituteFrederickMaryland
| | - Alexander Wlodawer
- Macromolecular Crystallography LaboratoryNational Cancer InstituteFrederickMaryland
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14
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Lubkowski J, Chan W, Wlodawer A. Opportunistic complexes of E. coli L-asparaginases with citrate anions. Sci Rep 2019; 9:11070. [PMID: 31363102 PMCID: PMC6667453 DOI: 10.1038/s41598-019-46432-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 06/20/2019] [Indexed: 11/09/2022] Open
Abstract
Active sites of enzymes are highly optimized for interactions with specific substrates, thus binding of opportunistic ligands is usually observed only in the absence of native substrates or products. However, during growth of crystals required for structure determination enzymes are often exposed to conditions significantly divergent from the native ones, leading to binding of unexpected ligands to active sites even in the presence of substrates. Failing to recognize this possibility may lead to incorrect interpretation of experimental results and to faulty conclusions. Here, we present several examples of binding of a citrate anion to the active sites of E. coli L-asparaginases I and II, even in the presence of the native substrate, L-Asn. A part of this report focuses on a comprehensive re-interpretation of structural results published previously for complexes of type I L-asparaginase (EcAI) from E. coli. In two re-refined structures a citrate anion forms an acyl-enzyme reaction intermediate with the catalytic threonine. These results emphasize the importance of careful and critical analysis during interpretation of crystallographic data.
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Affiliation(s)
- Jacek Lubkowski
- Macromolecular Crystallography Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA.
| | - Waikin Chan
- Department of Bioinformatics and Computational Biology and The Proteomics and Metabolomics Core Facility, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
| | - Alexander Wlodawer
- Macromolecular Crystallography Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA
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15
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Schalk AM, Antansijevic A, Caffrey M, Lavie A. Experimental Data in Support of a Direct Displacement Mechanism for Type I/II L-Asparaginases. J Biol Chem 2016; 291:5088-100. [PMID: 26733195 DOI: 10.1074/jbc.m115.699884] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Indexed: 01/02/2023] Open
Abstract
Bacterial L-asparaginases play an important role in the treatment of certain types of blood cancers. We are exploring the guinea pig L-asparaginase (gpASNase1) as a potential replacement of the immunogenic bacterial enzymes. The exact mechanism used by L-asparaginases to catalyze the hydrolysis of asparagine into aspartic acid and ammonia has been recently put into question. Earlier experimental data suggested that the reaction proceeds via a covalent intermediate using a ping-pong mechanism, whereas recent computational work advocates the direct displacement of the amine by an activated water. To shed light on this controversy, we generated gpASNase1 mutants of conserved active site residues (T19A, T116A, T19A/T116A, K188M, and Y308F) suspected to play a role in hydrolysis. Using x-ray crystallography, we determined the crystal structures of the T19A, T116A, and K188M mutants soaked in asparagine. We also characterized their steady-state kinetic properties and analyzed the conversion of asparagine to aspartate using NMR. Our structures reveal bound asparagine in the active site that has unambiguously not formed a covalent intermediate. Kinetic and NMR assays detect significant residual activity for all of the mutants. Furthermore, no burst of ammonia production was observed that would indicate covalent intermediate formation and the presence of a ping-pong mechanism. Hence, despite using a variety of techniques, we were unable to obtain experimental evidence that would support the formation of a covalent intermediate. Consequently, our observations support a direct displacement rather than a ping-pong mechanism for l-asparaginases.
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Affiliation(s)
- Amanda M Schalk
- From the Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, Illinois 60607 and
| | - Aleksandar Antansijevic
- From the Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, Illinois 60607 and
| | - Michael Caffrey
- From the Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, Illinois 60607 and
| | - Arnon Lavie
- From the Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, Illinois 60607 and the Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois 60612
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16
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Ali U, Naveed M, Ullah A, Ali K, Shah SA, Fahad S, Mumtaz AS. L-asparaginase as a critical component to combat Acute Lymphoblastic Leukaemia (ALL): A novel approach to target ALL. Eur J Pharmacol 2015; 771:199-210. [PMID: 26698391 DOI: 10.1016/j.ejphar.2015.12.023] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 12/08/2015] [Accepted: 12/10/2015] [Indexed: 02/02/2023]
Abstract
L-asparaginase, an anti-leukaemic drug that has been approved for clinical use for many years in the treatment of childhood Acute Lymphoblastic Leukaemia (ALL), is obtained from bacterial origin (Escherichia coli and Erwinia carotovora). The efficacy of L-asparaginase has been discussed for the past 40 years, and an ideal substitute for the enzyme has not yet been developed. The early clearance from plasma (short half-life) and requirement for multiple administrations and hence frequent physician visits make the overall treatment cost quite high. In addition, a high rate of allergic reactions in patients receiving treatment with the enzyme isolated from bacterial sources make its clinical application challenging. For these reasons, various attempts are being made to overcome these barriers. Therefore, the present article reviews studies focused on seeking substitutes for L-asparaginase through alternative sources including bacteria, fungi, actinomycetes, algae and plants to overcome these limitations. In addition, the role of chemical modifications and protein engineering approaches to enhance the drug's efficacy are also discussed. Moreover, an overview has also been provided in the current review regarding the contradiction among various researchers regarding the significance of the enzyme's glutaminase activity.
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Affiliation(s)
- Usman Ali
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China
| | - Muhammad Naveed
- Department of Biochemistry and Molecular Biology, University of Gujrat, Pakistan
| | - Abid Ullah
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China
| | - Khadija Ali
- Department of Environmental Sciences, International Islamic University, Islamabad, Pakistan
| | - Sayed Afzal Shah
- Department of Plant Sciences, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad 45320, Pakistan
| | - Shah Fahad
- National Key Laboratory of Crop Genetic Improvement, MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China
| | - Abdul Samad Mumtaz
- Department of Plant Sciences, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad 45320, Pakistan.
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17
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Anishkin A, Vanegas JM, Rogers DM, Lorenzi PL, Chan WK, Purwaha P, Weinstein JN, Sukharev S, Rempe SB. Catalytic Role of the Substrate Defines Specificity of Therapeutic l-Asparaginase. J Mol Biol 2015; 427:2867-85. [DOI: 10.1016/j.jmb.2015.06.017] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Revised: 05/20/2015] [Accepted: 06/26/2015] [Indexed: 12/23/2022]
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18
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Aghaiypour K, Wlodawer A, Lubkowski J. Do bacterial L-asparaginases utilize a catalytic triad Thr-Tyr-Glu? BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1550:117-28. [PMID: 11755201 DOI: 10.1016/s0167-4838(01)00270-9] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The structures of Erwinia chrysanthemi L-asparaginase (ErA) complexed with the L- and D-stereoisomers of the suicide inhibitor, 6-diazo-5-oxy-norleucine, have been solved using X-ray crystallography and refined with data extending to 1.7 A. The distances between the Calpha atoms of the inhibitor molecules and the hydroxyl oxygen atoms of Thr-15 and Tyr-29 (1.20 and 1.60 A, respectively) clearly indicate the presence of covalent bonds between these moieties, confirming the nucleophilic role of Thr-15 during the first stage of enzymatic reactions and also indicating direct involvement of Tyr-29. The factors responsible for activating Tyr-29 remain unclear, although some structural changes around Ser-254', Asp-96, and Glu-63, common to both complexes, suggest that those residues play a function. The role of Glu-289' as the activator of Tyr-29, previously postulated for the closely related Pseudomonas 7A L-glutaminase-asparaginase, is not confirmed in this study, due to the lack of interactions between these residues in these complexes and in holoenzymes. The results reported here are consistent with previous reports that mutants of Escherichia coli L-asparaginase lacking Glu-289 remain catalytically active and prove the catalytic roles of both Thr-15 and Tyr-29, while still leaving open the question of the exact mechanism resulting in the unusual chemical properties of these residues.
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Affiliation(s)
- K Aghaiypour
- Macromolecular Crystallography Laboratory, National Cancer Institute at Frederick, Frederick, MD 21702, USA
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19
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Schmidt HL, Werner RA, Rossmann A. 18O pattern and biosynthesis of natural plant products. PHYTOCHEMISTRY 2001; 58:9-32. [PMID: 11524109 DOI: 10.1016/s0031-9422(01)00017-6] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Oxygen atoms in plant products originate from CO(2), H(2)O and O(2), precursors with quite different delta18O values. Furthermore their incorporation by different reactions implies isotope effects. On this base the resulting non-statistical 18O distributions in natural compounds are discussed. The delta18O value of cellulose is correlated to that of the leaf water, and the observed 18O enrichment (approximately +27 per thousand) is generally attributed to an equilibrium isotope effect between carbonyl groups and water. However, as soluble and heterotrophically synthesised carbohydrates show other correlations, a non-statistical 18O distribution - originating from individual biosynthetic reactions - is postulated for carbohydrates. Similarly, the delta18O values of organic acids, carbonyl compounds, alcohols and esters indicate water-correlated, but individual 18O abundances (e.g. O from acyl groups approximately +19% above water), depending upon origin and biosyntheses. Alcoholic groups introduced by monooxygenase reactions, e.g. in sterols and phenols, show delta18O values near +5 per thousand, in agreement with an assumed isotope fractionation factor of approximately 1.02 on the reaction with atmospheric oxygen (delta18O=+23.5 per thousand). Correspondingly, a "thermodynamically ordered isotope distribution" is only observed for oxygen in some functional groups correlated to an origin from CO(2) and H(2)O, not from O(2). The individual isotopic increments of functional groups permit the prediction of global delta18O values of natural compounds on the basis of their biosynthesis.
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Affiliation(s)
- H L Schmidt
- Technische Universität München, Lehrstuhl für Biologische Chemie, Vöttinger Str. 40, D-85350 Freising-Weihenstephan, Germany.
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20
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Derst C, Henseling J, Röhm KH. Engineering the substrate specificity of Escherichia coli asparaginase. II. Selective reduction of glutaminase activity by amino acid replacements at position 248. Protein Sci 2000; 9:2009-17. [PMID: 11106175 PMCID: PMC2144453 DOI: 10.1110/ps.9.10.2009] [Citation(s) in RCA: 113] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The use of Escherichia coli asparaginase II as a drug for the treatment of acute lymphoblastic leukemia is complicated by the significant glutaminase side activity of the enzyme. To develop enzyme forms with reduced glutaminase activity, a number of variants with amino acid replacements in the vicinity of the substrate binding site were constructed and assayed for their kinetic and stability properties. We found that replacements of Asp248 affected glutamine turnover much more strongly than asparagine hydrolysis. In the wild-type enzyme, N248 modulates substrate binding to a neighboring subunit by hydrogen bonding to side chains that directly interact with the substrate. In variant N248A, the loss of transition state stabilization caused by the mutation was 15 kJ mol(-1) for L-glutamine compared to 4 kJ mol(-1) for L-aspartic beta-hydroxamate and 7 kJ mol(-1) for L-asparagine. Smaller differences were seen with other N248 variants. Modeling studies suggested that the selective reduction of glutaminase activity is the result of small conformational changes that affect active-site residues and catalytically relevant water molecules.
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Affiliation(s)
- C Derst
- Philipps University, Institute of Physiological Chemistry, Marburg (Lahn), Germany
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21
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Aung HP, Bocola M, Schleper S, Röhm KH. Dynamics of a mobile loop at the active site of Escherichia coli asparaginase. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1481:349-59. [PMID: 11018727 DOI: 10.1016/s0167-4838(00)00179-5] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Asparaginase II from Escherichia coli is well-known member of the bacterial class II amidohydrolases. Enzymes of this family utilize a peculiar catalytic mechanism in which a pair of threonine residues play pivotal roles. Another common feature is a mobile surface loop that closes over the active site when the substrates is bound. We have studied the motion of the loop by stopped-flow experiments using the fluorescence of tryptophan residues as the spectroscopic probe. With wild-type enzyme the fluorescence of the only tryptophan, W66, was monitored. Here asparagine induced a rapid closure of the loop. The rate constants of the process (100-150 s(-1) at 4 degrees C) were considerably higher than those of the rate-limiting catalytic step. A more selective spectroscopic probe was generated by replacing W66 with tyrosine and Y25, a component of the loop, with tryptophan. In the resulting enzyme variant, k(cat) and the rate of loop movement were reduced by factors of 10(2) and >10(3), respectively, while substrate binding was unaffected. This indicates that the presence of tyrosine in position 25 is essential for both loop closure and catalysis. Numerical simulations of the observed transients are consistent with a model where loop closure is an absolute prerequisite for substrate turnover.
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Affiliation(s)
- H P Aung
- Chemistry Department, University of Yangon, Myanmar
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22
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Lubkowski J, Palm GJ, Gilliland GL, Derst C, Röhm KH, Wlodawer A. Crystal structure and amino acid sequence of Wolinella succinogenes L-asparaginase. EUROPEAN JOURNAL OF BIOCHEMISTRY 1996; 241:201-7. [PMID: 8898907 DOI: 10.1111/j.1432-1033.1996.0201t.x] [Citation(s) in RCA: 80] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The amino acid sequence and tertiary structure of Wolinella succinogenes L-asparaginase were determined, and were compared with the structures of other type-II bacterial L-asparaginases. Each chain of this homotetrameric enzyme consists of 330 residues. The amino acid sequence is 40-50% identical to the sequences of related proteins from other bacterial sources, and all residues previously shown to be crucial for the catalytic action of these enzymes are identical. Differences between the amino acid sequence of W. succinogenes L-asparaginase and that of related enzymes are discussed in terms of the possible influence on the substrate specificity. The overall fold of the protein subunit is almost identical to that observed for other L-asparaginases. Two fragments in each subunit, a very highly flexible loop (approximately 20 amino acids) that forms part of the active site, and the N-terminus (two amino acids), are not defined in the structure. The orientation of Thr14, a residue probably involved in the catalytic activity, indicates the absence of ligand in the active-site pocket. The rigid part of the active site, which includes the asparaginase triad Thr93-Lys 166-Asp94, is structurally very highly conserved with equivalent regions found in other type-II bacterial L-asparaginases.
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Affiliation(s)
- J Lubkowski
- Macromolecular Structure Laboratory, NCI-Frederick Cancer Research and Development Center, ABL-Basic Research Programm, Frederick, Maryland, USA
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23
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Palm GJ, Lubkowski J, Derst C, Schleper S, Röhm KH, Wlodawer A. A covalently bound catalytic intermediate in Escherichia coli asparaginase: crystal structure of a Thr-89-Val mutant. FEBS Lett 1996; 390:211-6. [PMID: 8706862 DOI: 10.1016/0014-5793(96)00660-6] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Escherichia coli asparaginase II catalyzes the hydrolysis of L-asparagine to L-aspartate via a threonine-bound acyl-enzyme intermediate. A nearly inactive mutant in which one of the active site threonines, Thr-89, was replaced by valine was constructed, expressed, and crystallized. Its structure, solved at 2.2 A resolution, shows high overall similarity to the wild-type enzyme, but an aspartyl moiety is covalently bound to Thr-12, resembling a reaction intermediate. Kinetic analysis confirms the deacylation deficiency, which is also explained on a structural basis. The previously identified oxyanion hole is described in more detail.
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Affiliation(s)
- G J Palm
- Macromolecular Structure Laboratory, NCI-Frederick Cancer Research and Development Center, Frederick, MD 21702-1201, USA
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24
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Zhang N, Clarke F, Di Trapani G, Keough D, Beacham I. Guinea pig serum L-asparaginase: purification, and immunological relationship to liver L-asparaginase and serum L-asparaginases in other mammals. Comp Biochem Physiol B Biochem Mol Biol 1995; 112:607-12. [PMID: 8590375 DOI: 10.1016/0305-0491(95)00106-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
L-asparaginase, an enzyme used in the treatment of acute lymphocytic leukemia, is found in the serum of only a few mammalian groups, including the guinea pig and its close relatives in the superfamily Cavioidea. This report describes the purification and characterization of L-asparaginase from guinea pig serum. Antiserum against the purified enzyme cross-reacted with sera from other Cavioidean species but not with mouse serum. Relatively weak cross-reaction with unpurified L-asparaginase in guinea pig liver indicates a significant degree of evolutionary divergence.
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Affiliation(s)
- N Zhang
- Faculty of Science and Technology, Griffith University, Nathan, Brisbane, Qld, Australia
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25
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Miller M, Rao JK, Wlodawer A, Gribskov MR. A left-handed crossover involved in amidohydrolase catalysis. Crystal structure of Erwinia chrysanthemi L-asparaginase with bound L-aspartate. FEBS Lett 1993; 328:275-9. [PMID: 8348975 DOI: 10.1016/0014-5793(93)80943-o] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The crystal structure of L-asparaginase from Erwinia chrysanthemi in the presence and absence of L-aspartate was determined at 1.8 A resolution. Conserved residues in a left-handed crossover (a rare occurrence in protein structures) link pairs of dimers into the catalytically active tetrameric form of the enzyme. The structure of ErA containing bound aspartic acid shows that this unusual strand connectivity is an essential part of the active site architecture, responsible for releasing the product of the enzymatic hydrolysis. The orientation of the bound aspartate indicates for the first time a threonine residue as a catalytic nucleophile.
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Affiliation(s)
- M Miller
- Macromolecular Structure Laboratory, NCI-FCRDC, Frederick, MD 21702
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26
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Swain AL, Jaskólski M, Housset D, Rao JK, Wlodawer A. Crystal structure of Escherichia coli L-asparaginase, an enzyme used in cancer therapy. Proc Natl Acad Sci U S A 1993; 90:1474-8. [PMID: 8434007 PMCID: PMC45896 DOI: 10.1073/pnas.90.4.1474] [Citation(s) in RCA: 194] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The crystal structure of Escherichia coli asparaginase II (EC 3.5.1.1), a drug (Elspar) used for the treatment of acute lymphoblastic leukemia, has been determined at 2.3 A resolution by using data from a single heavy atom derivative in combination with molecular replacement. The atomic model was refined to an R factor of 0.143. This enzyme, active as a homotetramer with 222 symmetry, belongs to the class of alpha/beta proteins. Each subunit has two domains with unique topological features. On the basis of present structural evidence consistent with previous biochemical studies, we propose locations for the active sites between the N- and C-terminal domains belonging to different subunits and postulate a catalytic role for Thr-89.
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Affiliation(s)
- A L Swain
- Macromolecular Structure Laboratory, National Cancer Institute-Frederick Cancer Research and Development Center, MD 21702-1201
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27
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Wehner A, Harms E, Jennings MP, Beacham IR, Derst C, Bast P, Röhm KH. Site-specific mutagenesis of Escherichia coli asparaginase II. None of the three histidine residues is required for catalysis. EUROPEAN JOURNAL OF BIOCHEMISTRY 1992; 208:475-80. [PMID: 1521538 DOI: 10.1111/j.1432-1033.1992.tb17210.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Site-specific mutagenesis was used to replace the three histidine residues of Escherichia coli asparaginase II (EcA2) with other amino acids. The following enzyme variants were studied: [H87A]EcA2, [H87L]EcA2, [H87K]EcA2, [H183L]EcA2 and [H197L]EcA2. None of the mutations substantially affected the Km for L-aspartic acid beta-hydroxamate or impaired aspartate binding. The relative activities towards L-Asn, L-Gln, and l-aspartic acid beta-hydroxamate were reduced to the same extent, with residual activities exceeding 10% of the wild-type values. These data do not support a number of previous reports suggesting that histidine residues are essential for catalysis. Spectroscopic characterization of the modified enzymes allowed the unequivocal assignment of the histidine resonances in 1H-NMR spectra of asparaginase II. A histidine signal previously shown to disappear upon aspartate binding is due to His183, not to the highly conserved His87. The fact that [H183L]EcA2 has normal activity but greatly reduced stability in the presence of urea suggests that His183 is important for the stabilization of the native asparaginase tetramer. 1H-NMR and fluorescence spectroscopy indicate that His87 is located in the interior of the protein, possibly adjacent to the active site.
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Affiliation(s)
- A Wehner
- Institut für Physiologische Chemie, Philipps-Universität, Marburg, Federal Republic of Germany
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28
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Substrate specificity and reaction mechanism of human glycoasparaginase. The N-glycosidic linkage of various glycoasparagines is cleaved through a reaction mechanism similar to L-asparaginase. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(19)50505-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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29
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Harms E, Wehner A, Aung HP, Röhm KH. A catalytic role for threonine-12 of E. coli asparaginase II as established by site-directed mutagenesis. FEBS Lett 1991; 285:55-8. [PMID: 1906013 DOI: 10.1016/0014-5793(91)80723-g] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A threonine-12 to alanine mutant of E. coli asparaginase II (EC 3.5.1.1) has less than 0.01% of the activity of wild-type enzyme. Both tertiary and quaternary structure of the enzyme are essentially unaffected by the mutation; thus the activity loss seems to be the result of a direct impairment of catalytic function. As aspartate is still bound by the mutant enzyme, Thr-12 appears not be involved in substrate binding.
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Affiliation(s)
- E Harms
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907
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30
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Risley JM, van Etten RL. Properties and Chemical Applications of 18O Isotope Shifts in 13C and 15N Nuclear Magnetic Resonance Spectroscopy. ISOTOPE EFFECTS IN NMR SPECTROSCOPY 1990. [DOI: 10.1007/978-3-642-74835-6_3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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31
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Mega TL, Van Etten RL. Oxygen exchange and bond cleavage reactions of carbohydrates studied using the 18O isotope shift in 13C NMR spectroscopy. BASIC LIFE SCIENCES 1990; 56:85-93. [PMID: 2078181 DOI: 10.1007/978-1-4684-5868-8_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- T L Mega
- Purdue University, Chemistry Department, W. Lafayette, IN 47907
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32
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Bagert U, Röhm KH. On the role of histidine and tyrosine residues in E. coli asparaginase. Chemical modification and 1H-nuclear magnetic resonance studies. BIOCHIMICA ET BIOPHYSICA ACTA 1989; 999:36-41. [PMID: 2679893 DOI: 10.1016/0167-4838(89)90026-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The relative importance of tyrosine and histidine residues for the catalytic action of Escherichia coli asparaginase (L-asparagine amidohydrolase, EC 3.5.1.1) was studied by chemical modification and 1H-NMR spectroscopy. We show that, under appropriate reaction conditions, N-bromosuccinimide (NBS) as well as diazonium-1H-tetrazole (DHT) inactivate by selectively modifying two tyrosine residues per asparaginase subunit without affecting histidyl moieties. We further show that diethyl pyrocarbonate (DEP), a reagent considered specific for histidine, also modifies tyrosine residues in asparaginase. Thus, inactivation of the enzyme by DEP is not indicative of histidine residues being involved in catalysis. In 1H-nuclear magnetic resonance (NMR) spectra of asparaginase signals from all three histidine residues were identified. By measuring the pH dependencies of these resonances, pKa values of 7.0 and 5.8 were derived for two of the histidines. Titration with aspartate which tightly binds to the enzyme at low pH strongly reduced the signal amplitude of the pKa 7 histidyl moiety as well as those of resonances of one or more tyrosine residues. This suggests that tyrosine and histidine are indeed constituents of the active site.
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Affiliation(s)
- U Bagert
- Institute of Physiological Chemistry, Philipps University Marburg Lahn, F.R.G
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33
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Röhm KH, Van Etten RL. Catalysis by hog-kidney aminoacylase does not involve a covalent intermediate. EUROPEAN JOURNAL OF BIOCHEMISTRY 1986; 160:327-32. [PMID: 3769932 DOI: 10.1111/j.1432-1033.1986.tb09975.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Hog kidney aminoacylase (N-acylamino acid amidohydrolase; acylase I) is shown to catalyze the exchange of acetate oxygens with water at a significant rate only when alanine is present simultaneously. These studies, conducted using the 18O-isotope induced shift on 13C-NMR spectra, provide evidence in favor of a linear kinetic mechanism as opposed to a 'ping-pong' double-displacement mechanism. At pH values above neutrality, aminoacylase I also catalyzes the exchange of alanine oxygens with those of water. Ionic strength and pH effects on the kinetics of aminoacylase I are examined and the results are interpreted in terms of a model of the enzyme active site.
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