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Sperry MM, Murugan NJ, Levin M. Studying Protista WBR and Repair Using Physarum polycephalum. Methods Mol Biol 2022; 2450:51-67. [PMID: 35359302 PMCID: PMC9761523 DOI: 10.1007/978-1-0716-2172-1_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Physarum polycephalum is a protist slime mould that exhibits a high degree of responsiveness to its environment through a complex network of tubes and cytoskeletal components that coordinate behavior across its unicellular, multinucleated body. Physarum has been used to study decision making, problem solving, and mechanosensation in aneural biological systems. The robust generative and repair capacities of Physarum also enable the study of whole-body regeneration within a relatively simple model system. Here we describe methods for growing, imaging, quantifying, and sampling Physarum that are adapted for investigating regeneration and repair.
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Affiliation(s)
- Megan M Sperry
- Wyss Institute for Biologically Inspired Engineering at Harvard University, Boston, MA, USA
- Department of Biology, Tufts University, Medford, MA, USA
| | - Nirosha J Murugan
- Department of Biology, Algoma University, Sault Ste. Marie, ON, Canada.
- Allen Discovery Center at Tufts University, Medford, MA, USA.
| | - Michael Levin
- Wyss Institute for Biologically Inspired Engineering at Harvard University, Boston, MA, USA.
- Department of Biology, Tufts University, Medford, MA, USA.
- Allen Discovery Center at Tufts University, Medford, MA, USA.
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Zou X, Cheng C, Feng J, Song X, Lin M, Yang ST. Biosynthesis of polymalic acid in fermentation: advances and prospects for industrial application. Crit Rev Biotechnol 2019; 39:408-421. [DOI: 10.1080/07388551.2019.1571008] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Xiang Zou
- College of Pharmaceutical Sciences, Chongqing Engineering Research Center for Pharmaceutical Process and Quality Control, Southwest University, Chongqing, PR China
| | - Chi Cheng
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH, USA
| | - Jun Feng
- College of Pharmaceutical Sciences, Chongqing Engineering Research Center for Pharmaceutical Process and Quality Control, Southwest University, Chongqing, PR China
| | - Xiaodan Song
- College of Pharmaceutical Sciences, Chongqing Engineering Research Center for Pharmaceutical Process and Quality Control, Southwest University, Chongqing, PR China
| | - Meng Lin
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH, USA
| | - Shang-Tian Yang
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH, USA
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Petruseva IO, Tikhanovich IS, Maltseva EA, Safronov IV, Lavrik OI. Photoactivated DNA analogs of substrates of the nucleotide excision repair system and their interaction with proteins of NER-competent HeLa cell extract. BIOCHEMISTRY (MOSCOW) 2009; 74:491-501. [PMID: 19538122 DOI: 10.1134/s0006297909050034] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Photoactivated DNA analogs of nucleotide excision repair (NER) substrates have been created that are 48-mer duplexes containing in internal positions pyrimidine nucleotides with bulky substituents imitating lesions. Fluorochloroazidopyridyl, anthracenyl, and pyrenyl groups introduced using spacer fragments at 4N and 5C positions of dCMP and dUMP were used as model damages. The gel retardation and photo-induced affinity modification techniques were used to study the interaction of modified DNA duplexes with proteins in HeLa cell extracts containing the main components of NER protein complexes. It is shown that the extract proteins selectively bind and form covalent adducts with the model DNA. The efficiency and selectivity of protein modification depend on the structure of used DNA duplex. Apparent molecular masses of extract proteins, undergoing modification, were estimated. Mutual influence of simultaneous presence of extract proteins and recombinant NER protein factors XPC-HR23B, XPA, and RPA on interaction with the model DNA was analyzed. The extract proteins and RPA competed for interaction with photoactive DNA, mutually decreasing the yield of modification products. In this case the presence of extract proteins at particular concentrations tripled the increase in yield of covalent adducts formed by XPC. It is supposed that the XPC subunit interaction with DNA is stimulated by endogenous HR23B present in the extract. Most likely, the mutual effect of XPA and extract proteins stimulating formation of covalent adducts with model DNA is due to the interaction of XPA with endogenous RPA of the extract. A technique based on the use of specific antibodies revealed that RPA present in the extract is a modification target for photoactive DNA imitating NER substrates.
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Affiliation(s)
- I O Petruseva
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, 630090, Russia.
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Pinchai N, Lee BS, Holler E. Stage specific expression of poly(malic acid)-affiliated genes in the life cycle of Physarum polycephalum. Spherulin 3b and polymalatase. FEBS J 2006; 273:1046-55. [PMID: 16478477 DOI: 10.1111/j.1742-4658.2006.05131.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Polymalic acid is receiving interest as a unique biopolymer of the plasmodia of mycetozoa and recently as a biogenic matrix for the synthesis of devices for drug delivery. The acellular slime mold Physarum polycephalum is characterized by two distinctive growth phases: uninucleated amoebae and multinucleated plasmodia. In adverse conditions, plasmodia reversibly transform into spherules. Only plasmodia synthesize poly(malic acid) (PMLA) and PMLA-hydrolase (polymalatase). We have performed suppression subtractive hybridization (SSH) of cDNA from amoebae and plasmodia to identify plasmodium-specific genes involved in PMLA metabolism. We found cDNA encoding a plasmodium-specific, spherulin 3a-like polypeptide, NKA48 (spherulin 3b), but no evidence for a PMLA-synthetase encoding transcript. Inhibitory RNA (RNAi)-induced knockdown of NKA48-cDNA generated a severe reduction in the level of PMLA suggesting that spherulin 3b functioned in regulating the level of PMLA. Unexpectedly, cDNA of polymalatase was not SSH-selected, suggesting its presence also in amoebae. Quantitative PCR then revealed low levels of mRNA in amoebae, high levels in plasmodia, and also low levels in spherules, in agreement with the expression under transcriptional regulation in these cells.
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Affiliation(s)
- Nadthanan Pinchai
- Institut für Biophysik und Physikalische Biochemie der Universität Regensburg, Germany
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Göttler T, Holler E. Screening for beta-poly(L-malate) binding proteins by affinity chromatography. Biochem Biophys Res Commun 2006; 341:1119-27. [PMID: 16476581 DOI: 10.1016/j.bbrc.2006.01.064] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2006] [Accepted: 01/17/2006] [Indexed: 10/25/2022]
Abstract
Poly(beta-L-malic acid) is a cell type-specific polymer of myxomycetes (true slime molds) with the physiological role to organize mobility of certain proteins over the giant multinucleated plasmodia. We have developed an affinity chromatography employing 1,6-diamino-n-hexane-Sepharose-coupled poly(malic acid) to identify such proteins in cellular extracts of Physarum polycephalum. Molecular masses were measured by SDS-PAGE and non-denaturing PAGE after silver staining and/or Western blotting. Protein complexes/subunits were detected by 2-dimensional non-denaturing PAGE/SDS-PAGE. A simplified gel shift experiment displayed binding to fragmented calf thymus DNA. Nuclei were richest in poly(malate) binding proteins followed by cytoplasm and membranes. A protein of 370 kDa dissociated into 11 subunits of 11-29 kDa, indicative of a highly complex protein. This and other proteins displayed binding to nucleic acid in gel shift experiments. Poly(malate) is considered a structural and functional equivalent of long contiguous aspartate repeats in proteins of eukaryotes.
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Affiliation(s)
- Thomas Göttler
- Institut für Biophysik und Physikalische Biochemie, Universität Regensburg, D-93040 Regensburg, Germany
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Highly efficient modification of DNA polymerase β under conditions of direct and sensitized activation of photoreactive DNAs. Modification of cell extract proteins. Russ Chem Bull 2005. [DOI: 10.1007/s11172-005-0400-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Karl M, Anderson R, Holler E. Injection of poly(β-l-malate) into the plasmodium of Physarum polycephalum shortens the cell cycle and increases the growth rate. ACTA ACUST UNITED AC 2004; 271:3805-11. [PMID: 15373826 DOI: 10.1111/j.1432-1033.2004.04299.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Poly(beta-L-malate) (PMLA) has been reported as an unconventional, physiologically important biopolymer in plasmodia of myxomycetes, and has been proposed to function in the storage and transport of nuclear proteins by mimicking the phospho(deoxy)ribose backbone of nucleic acids. It is distributed in the cytoplasm and especially in the nuclei of these giant, multinucleate cells. We report here for the first time an increase in growth rate and a shortening of the cell cycle after the injection of purified PMLA. By comparing two strains of Physarum polycephalum that differed in their production levels of PMLA, it was found that growth activation and cell cycle shortening correlated with the relative increases of PMLA levels in the cytoplasm or the nuclei. Growth rates of a low PMLA producer strain (LU897 x LU898) were increased by 40-50% while those of a high producer strain (M(3)CVIII) were increased by only 0-17% in comparison with controls. In both strains, shortening of the cell cycle occurred to a similar extent (7.2-9.5%), and this was associated with similar increases in nuclear PMLA levels. The effects showed saturation dependences with regard to the amount of injected PMLA. A steep rise of intracellular PMLA shortly after injection was followed by the appearance of histone H1 in the cytoplasm. The increase in growth rate, the shortening of the cell cycle duration and the appearance of H1 in the cytoplasm suggest that PMLA competes with nucleic acids in binding to proteins that control translation and/or transcription. Thus, PMLA could play an important role in the coordination of molecular pathways that are responsible for the synchronous functioning of the multinucleate plasmodium.
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Affiliation(s)
- Michael Karl
- Institut für Biophysik und Physikalische Biochemie der Universität Regensburg, D93040 Regensburg, Germany
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Karl M, Gasselmaier B, Krieg RC, Holler E. Localization of fluorescence-labeled poly(malic acid) to the nuclei of the plasmodium of Physarum polycephalum. EUROPEAN JOURNAL OF BIOCHEMISTRY 2003; 270:1536-42. [PMID: 12654009 DOI: 10.1046/j.1432-1033.2003.03521.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The nuclei in the plasmodium of Physarum polycephalum, as of other myxomycetes, contain high amounts of polymalate, which has been proposed to function as a scaffold for the carriage and storage of several DNA-binding proteins [Angerer, B. and Holler, E. (1995) Biochemistry 34, 14741-14751]. By delivering fluorescence-labeled polymalate into a growing plasmodium by injection, we observed microscopic staining of nuclei in agreement with the proposed function. The fluorescence intensity was highest during the reconstruction phase of the nuclei. To examine whether the delivery was under the control of polymalatase or related proteins [Karl, M. & Holler, E. (1998) Eur. J. Biochem.251, 405-412], the cellular distribution of these proteins was also examined by staining with antibodies against polymalatase. Double-stained plasmodia revealed a fluorescent halo around each fluorescent nucleus during the reconsititution. Fluorescent nuclei were not observed when the hydroxyl terminus of polymalate, known to be essential for the binding of polymalatase, was blocked by labeling with fluorescein-5-isothiocyanate. By immune precipitation, it was shown that polymalate and polymalatase or related proteins were in the precipitate. It is concluded that polymalate is delivered to the surface of nuclei in the complex with polymalatase or related proteins. The complex dissociates, and polymalate translocates into the nucleus, while polymalatase or related proteins remain at the surface.
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Affiliation(s)
- Miachael Karl
- Institut für Biophysik und Physikalische Biochemie, Germany
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Lavrik OI, Kolpashchikov DM, Prasad R, Sobol RW, Wilson SH. Binary system for selective photoaffinity labeling of base excision repair DNA polymerases. Nucleic Acids Res 2002; 30:e73. [PMID: 12136121 PMCID: PMC135774 DOI: 10.1093/nar/gnf073] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A system of photoaffinity reagents for selective labeling of DNA polymerases in extracts has been examined. To create the photoreactive DNA probe in situ, DNA substrates containing a synthetic abasic site are incubated in mouse embryonic fibroblast (MEF) cellular extract in the presence of base-substituted arylazido derivatives of dNTPs. This results in synthesis of a photoreactive long patch base excision repair (BER) intermediate. The arylazido photoreactive group is then activated through energy transfer from the pyrene group of a dNTP analog (Pyr-dUTP), following 365 nm UV light exposure. Pyr-dUTP binds to the active site of DNA polymerases, and the pyrene group, when excited by 365 nm UV light, activates the nearby photoreactive group in the BER intermediate resulting in crosslinking of DNA-bound DNA polymerases. Under these conditions, various DNA binding proteins that are unable to bind Pyr-dUTP are not crosslinked to DNA. DNA polymerase beta is the predominant crosslinked protein observed in the MEF extract. In contrast, several other DNA binding proteins are labeled under conditions of direct UV light activation of the photoreactive group at 312 nm. This study illustrates use of a new method of selective labeling of DNA polymerases in a crude cellular extract.
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Affiliation(s)
- Olga I Lavrik
- Laboratory of Structural Biology, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
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Doerhoefer S, Windisch C, Angerer B, Lavrik OI, Lee BS, Holler E. The DNA-polymerase inhibiting activity of poly(beta-l-malic acid) in nuclear extract during the cell cycle of Physarum polycephalum. EUROPEAN JOURNAL OF BIOCHEMISTRY 2002; 269:1253-8. [PMID: 11856359 DOI: 10.1046/j.1432-1033.2002.02765.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The naturally synchronous plasmodia of myxomycetes synthesize poly(beta-l-malic acid), which carries out cell-specific functions. In Physarum polycephalum, poly(beta-l-malate) [the salt form of poly(beta-l-malic acid)] is highly concentrated in the nuclei, repressing DNA synthetic activity of DNA polymerases by the formation of reversible complexes. To test whether this inhibitory activity is cell-cycle-dependent, purified DNA polymerase alpha of P. polycephalum was added to the nuclear extract and the activity was measured by the incorporation of [3H]thymidine 5'-monophosphate into acid precipitable nick-activated salmon testis DNA. Maximum DNA synthesis by the reporter was measured in S-phase, equivalent to a minimum of inhibitory activity. To test for the activity of endogenous DNA polymerases, DNA synthesis was followed by the highly sensitive photoaffinity labeling technique. Labeling was observed in S-phase in agreement with the minimum of the inhibitory activity. The activity was constant throughout the cell cycle when the inhibition was neutralized by the addition of spermidine hydrochloride. Also, the concentration of poly(beta-l-malate) did not vary with the phase of the cell cycle [Schmidt, A., Windisch, C. & Holler, E. (1996) Nuclear accumulation and homeostasis of the unusual polymer poly(beta-l-malate) in plasmodia of Physarum polycephalum. Eur. J. Cell Biol. 70, 373-380]. To explain the variation in the cell cycle, a periodic competition for poly(beta-l-malate) between DNA polymerases and most likely certain histones was assumed. These effectors are synthesized in S-phase. By competition they displace DNA polymerase from the complex of poly(beta-l-malate). The free polymerases, which are no longer inhibited, engage in DNA synthesis. It is speculated that poly(beta-l-malate) is active in maintaining mitotic synchrony of plasmodia by playing the mediator between the periodic synthesis of certain proteins and the catalytic competence of DNA polymerases.
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Affiliation(s)
- Sabine Doerhoefer
- Institut für Biophysik und physikalische Biochemie, Universität, Regensburg, Germany
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Lebedeva NA, Kolpashchikov DM, Rechkunova NI, Khodyreva SN, Lavrik OI. A binary system of photoreagents for high-efficiency labeling of DNA polymerases. Biochem Biophys Res Commun 2001; 287:530-5. [PMID: 11554761 DOI: 10.1006/bbrc.2001.5623] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To increase the efficiency of photoaffinity labeling of DNA polymerases, a binary system of photoaffinity reagents was applied. Photoreactive radioactive primers were synthesized by DNA polymerases beta (pol beta) or DNA polymerase from Thermus thermophilus (pol Tte) using a template-primer duplex in the presence of a dTTP analogue containing 4-azidotetrafluorobenzoyl group linked via spacers of varying length to 5-position of uridine ring- 5-[N-(2,3,5,6-tetrafluoro-4-azidobenzoyl)-amino-trans-propenyl-1]-2'-deoxyuridine-5'-triphosphate (FAB-4-dUTP) or 5-[N-[[(2,3,5,6-tetrafluoro-4-azidobenzoyl)-butanoyl]-amino]-trans-3-aminopropenyl-1]-2'-deoxyuridine-5'-triphosphate (FAB-9-dUTP). The reaction mixtures were UV irradiated (lambda = 365-450 nm) in the absence or presence of a dTTP analog, containing a pyrene moiety-5-[N-(4-(1-pyrenyl)-butylcarbonyl)-amino-trans-propenyl-1]-2'-deoxyuridine-5'-triphosphate (Pyr- 8-dUTP) or 5-[N-(4-(1-pyrenyl)-ethylcarbonyl)-amino-trans-propenyl-1]-2'-deoxyuridine-5'-triphosphate (Pyr-6-dUTP). The most efficient crosslinking of both DNA polymerases was observed in the case of photoreactive DNA primer, carrying the FAB-4-dUMP moiety at the 3'-end, and Pyr-6-dUTP as a sensitizer. The binary system of photoaffinity reagents allows increasing photoaffinity labeling of the both DNA polymerases in comparison to the primer crosslinking without photosensitizer.
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Affiliation(s)
- N A Lebedeva
- Novosibirsk Institute of Bioorganic Chemistry, Siberian Division, Russian Academy of Sciences, Pr. Lavrentiev 8, 630090, Novosibirsk, Russian Federation
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Gasslmaier B, Krell CM, Seebach D, Holler E. Synthetic substrates and inhibitors of beta-poly(L-malate)-hydrolase (polymalatase). EUROPEAN JOURNAL OF BIOCHEMISTRY 2000; 267:5101-5. [PMID: 10931193 DOI: 10.1046/j.1432-1327.2000.01573.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Polymalatase from Physarum polycephalum calalysed the hydrolysis of beta-poly[L-malate] and of the synthetic compounds beta-di(L-malate), beta-tetra(L-malate), beta-tetra(L-malate) beta-propylester, and L-malate beta-methylester. Cyclic beta-tri(L-malate), cyclic beta-tetra(L-malate), and D-malate beta-methylester were not cleaved, but were competitive inhibitors. The O-terminal acetate of beta-tetra(L-malate) was neither a substrate nor an inhibitor. L-Malate was liberated; the Km, Ki and Vmax values were measured. The appearance of comparable amounts of beta-tri(L-malate), and beta-di(L-malate) during the cleavage of beta-tetra(L-malate) indicated a distributive mechanism for small substrates. The accumulation of a series of oligomers, peaking with the 11-mer and 12-mer in the absence of higher intermediates, indicated that the depolymerization of beta-poly(L-malate) was processive. The results indicate that beta-poly(L-malate) is anchored at its OH-terminus by the highly specific binding of the penultimate malyl residue. The malyl moieties beyond 12 residues downstream from the OH-terminus extend into a diffuse second, electrostatic binding site. The catalytic site joins the first binding site, accounting for the cleavage of the polymer into malate residues. It is proposed that the enzyme does not dissociate from beta-poly(L-malate) during hydrolysis, when both sites are filled with the polymer. When only the first binding site is filled, the reaction partitions at each oligomer between hydrolysis and dissociation.
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Affiliation(s)
- B Gasslmaier
- Institut für Biophysik und Physikalische Biochemie der Universität Regensburg, Germany
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The preparation of a photoreactive analogue of 2′,3′-dideoxyuridine 5′-triphosphate and its use for photoaffinity modification of human replication protein A. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2000. [DOI: 10.1007/bf02759159] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Willibald B, Bildl W, Lee BS, Holler E. Is beta-poly(L-malate) synthesis catalysed by a combination of beta-L-malyl-AMP-ligase and beta-poly(L-malate) polymerase? EUROPEAN JOURNAL OF BIOCHEMISTRY 1999; 265:1085-90. [PMID: 10518805 DOI: 10.1046/j.1432-1327.1999.00834.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
beta-Poly(L-malate) is supposed to function in the storage and transport of histones, DNA polymerases and other nuclear proteins in the giant syncytical cells (plasmodia) of myxomycetes. Here we report on the biosynthesis of [14C]beta-poly(L-malate) from injected L-[14C]malate in the plasmodium of Physarum polycephalum. The effects of KCN, arsenate, adenosine 5'-(alpha, beta-methylene)triphosphate, adenosine 5'-(beta, gamma-methylene)triphosphate, guanosine 5'-(beta, gamma-methylene)triphosphate, desulfo coenzyme A and phenylarsinoxid on beta-poly(L-malate) synthesis were studied after their coinjection with L-[14C]malate. The synthesis was not affected by KCN or desulfo coenzyme A, but was blocked by arsenate and adenosine 5'-(alpha,beta-methylene)triphosphate. The plasmodium lysate catalysed an L-malate-dependent ATP-[32P]pyrophosphate exchange, but was devoid of beta-poly(L-malate) synthetic activity under all experimental conditions tested. The results suggested an extramitochondrial synthesis of beta-poly(L-malate), involving the polymerization of beta-L-malyl-AMP. It is assumed that the lack of synthesis in the lysate is caused by the inactivation of beta-poly(L-malate) polymerase involving a cell injury kinase pathway. Because injected guanosine 5'-(beta, gamma-methylene)triphosphate blocks the synthesis, the injury signal is likely to be GTP dependent.
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Affiliation(s)
- B Willibald
- Institut für Biophysik und Physikalische Biochemie der Universität, Regensburg, Germany
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