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Sharon I, Hilvert D, Schmeing TM. Cyanophycin and its biosynthesis: not hot but very cool. Nat Prod Rep 2023; 40:1479-1497. [PMID: 37231979 DOI: 10.1039/d2np00092j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Covering: 1878 to early 2023Cyanophycin is a biopolymer consisting of a poly-aspartate backbone with arginines linked to each Asp sidechain through isopeptide bonds. Cyanophycin is made by cyanophycin synthetase 1 or 2 through ATP-dependent polymerization of Asp and Arg, or β-Asp-Arg, respectively. It is degraded into dipeptides by exo-cyanophycinases, and these dipeptides are hydrolyzed into free amino acids by general or dedicated isodipeptidase enzymes. When synthesized, chains of cyanophycin coalesce into large, inert, membrane-less granules. Although discovered in cyanobacteria, cyanophycin is made by species throughout the bacterial kingdom, and cyanophycin metabolism provides advantages for toxic bloom forming algae and some human pathogens. Some bacteria have developed dedicated schemes for cyanophycin accumulation and use, which include fine temporal and spatial regulation. Cyanophycin has also been heterologously produced in a variety of host organisms to a remarkable level, over 50% of the host's dry mass, and has potential for a variety of green industrial applications. In this review, we summarize the progression of cyanophycin research, with an emphasis on recent structural studies of enzymes in the cyanophycin biosynthetic pathway. These include several unexpected revelations that show cyanophycin synthetase to be a very cool, multi-functional macromolecular machine.
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Affiliation(s)
- Itai Sharon
- Department of Biochemistry and Centre de Recherche en Biologie Structurale, McGill University, Montréal, QC, Canada, H3G 0B1.
| | - Donald Hilvert
- Laboratory of Organic Chemistry, ETH Zürich, CH-8093 Zürich, Switzerland
| | - T Martin Schmeing
- Department of Biochemistry and Centre de Recherche en Biologie Structurale, McGill University, Montréal, QC, Canada, H3G 0B1.
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2
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Sharon I, Grogg M, Hilvert D, Schmeing TM. Structure and Function of the β-Asp-Arg Polymerase Cyanophycin Synthetase 2. ACS Chem Biol 2022; 17:670-679. [PMID: 35179888 DOI: 10.1021/acschembio.1c01007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cyanophycin is a biopolymer composed of long chains of β-Asp-Arg. It is widespread in nature, being synthesized by many clades of bacteria, which use it as a cellular reservoir of nitrogen, carbon, and energy. Two enzymes are known to produce cyanophycin: cyanophycin synthetase 1 (CphA1), which builds cyanophycin from the amino acids Asp and Arg by alternating between two separate reactions for backbone extension and side chain modification, and cyanophycin synthetase 2 (CphA2), which polymerizes β-Asp-Arg dipeptides. CphA2 is evolutionarily related to CphA1, but questions about CphA2's altered structure and function remain unresolved. Cyanophycin and related molecules have drawn interest as green biopolymers. Because it only has a single active site, CphA2 could be more useful than CphA1 for biotechnological applications seeking to produce modified cyanophycin. In this study, we report biochemical assays on nine cyanobacterial CphA2 enzymes and report the crystal structure of CphA2 from Gloeothece citriformis at 3.0 Å resolution. The structure reveals a homodimeric, three-domain architecture. One domain harbors the polymerization active site and the two other domains have structural roles. The structure and biochemical assays explain how CphA2 binds and polymerizes β-Asp-Arg and highlights differences in in vitro oligomerization and activity between CphA2 enzymes. Using the structure and distinct activity profile as a guide, we introduced a single point mutation that converted Gloeothece citriformis CphA2 from a primer-dependent enzyme into a primer-independent enzyme.
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Affiliation(s)
- Itai Sharon
- Department of Biochemistry and Centre de recherche en biologie structurale, McGill University, Montréal H3G 0B1, Quebec, Canada
| | - Marcel Grogg
- Laboratory of Organic Chemistry, ETH Zürich, CH-8093 Zürich, Switzerland
| | - Donald Hilvert
- Laboratory of Organic Chemistry, ETH Zürich, CH-8093 Zürich, Switzerland
| | - T. Martin Schmeing
- Department of Biochemistry and Centre de recherche en biologie structurale, McGill University, Montréal H3G 0B1, Quebec, Canada
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3
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Sharon I, Haque AS, Grogg M, Lahiri I, Seebach D, Leschziner AE, Hilvert D, Schmeing TM. Structures and function of the amino acid polymerase cyanophycin synthetase. Nat Chem Biol 2021; 17:1101-1110. [PMID: 34385683 DOI: 10.1038/s41589-021-00854-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Accepted: 07/08/2021] [Indexed: 12/13/2022]
Abstract
Cyanophycin is a natural biopolymer produced by a wide range of bacteria, consisting of a chain of poly-L-Asp residues with L-Arg residues attached to the β-carboxylate sidechains by isopeptide bonds. Cyanophycin is synthesized from ATP, aspartic acid and arginine by a homooligomeric enzyme called cyanophycin synthetase (CphA1). CphA1 has domains that are homologous to glutathione synthetases and muramyl ligases, but no other structural information has been available. Here, we present cryo-electron microscopy and X-ray crystallography structures of cyanophycin synthetases from three different bacteria, including cocomplex structures of CphA1 with ATP and cyanophycin polymer analogs at 2.6 Å resolution. These structures reveal two distinct tetrameric architectures, show the configuration of active sites and polymer-binding regions, indicate dynamic conformational changes and afford insight into catalytic mechanism. Accompanying biochemical interrogation of substrate binding sites, catalytic centers and oligomerization interfaces combine with the structures to provide a holistic understanding of cyanophycin biosynthesis.
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Affiliation(s)
- Itai Sharon
- Department of Biochemistry and Centre de Recherche en Biologie Structurale, McGill University, Montréal, Quebec, Canada
| | - Asfarul S Haque
- Department of Biochemistry and Centre de Recherche en Biologie Structurale, McGill University, Montréal, Quebec, Canada
| | - Marcel Grogg
- Laboratory of Organic Chemistry, ETH Zürich, Zürich, Switzerland
| | - Indrajit Lahiri
- Department of Cellular and Molecular Medicine, and Section of Molecular Biology, Division of Biological Sciences, University of California San Diego (UCSD), La Jolla, CA, USA
| | - Dieter Seebach
- Laboratory of Organic Chemistry, ETH Zürich, Zürich, Switzerland
| | - Andres E Leschziner
- Department of Cellular and Molecular Medicine, and Section of Molecular Biology, Division of Biological Sciences, University of California San Diego (UCSD), La Jolla, CA, USA
| | - Donald Hilvert
- Laboratory of Organic Chemistry, ETH Zürich, Zürich, Switzerland
| | - T Martin Schmeing
- Department of Biochemistry and Centre de Recherche en Biologie Structurale, McGill University, Montréal, Quebec, Canada.
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4
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Frommeyer M, Wiefel L, Steinbüchel A. Features of the biotechnologically relevant polyamide family "cyanophycins" and their biosynthesis in prokaryotes and eukaryotes. Crit Rev Biotechnol 2015; 36:153-64. [PMID: 25268179 DOI: 10.3109/07388551.2014.946467] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Cyanophycin, inclusions in cyanobacteria discovered by the Italian scientist Borzi in 1887, were characterized as a polyamide consisting of aspartic acid and arginine. Its synthesis in cyanobacteria was analyzed regarding growth conditions, responsible gene product, requirements, polymer structure and properties. Heterologous expression of diverse cyanophycin synthetases (CphA) in Escherichia coli enabled further enzyme characterization. Cyanophycin is a polyamide with variable composition and physiochemical properties dependent on host and cultivation conditions in contrast to the extracellular polyamides poly-γ-glutamic acid and poly-ε-l-lysine. Furthermore, recombinant prokaryotes and transgenic eukaryotes, including plants expressing different cphA genes, were characterized as suitable for production of insoluble cyanophycin regarding higher yields and modified composition for other requirements and applications. In addition, cyanophycin was characterized as a source for the synthesis of polyaspartic acid or N-containing bulk chemicals and dipeptides upon chemical treatment or degradation by cyanophycinases, respectively. Moreover, water-soluble cyanophycin derivatives with altered amino acid composition were isolated from transgenic plants, yeasts and recombinant bacteria. Thereby, the range of dipeptides could be extended by biological processes and by chemical modification, thus increasing the range of applications for cyanophycin and its dipeptides, including agriculture, food supplementations, medical and cosmetic purposes, synthesis of the polyacrylate substitute poly(aspartic acid) and other applications.
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Affiliation(s)
- Maja Frommeyer
- a Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität , Münster , Germany and
| | - Lars Wiefel
- a Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität , Münster , Germany and
| | - Alexander Steinbüchel
- a Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität , Münster , Germany and.,b Environmental Science Department, King Abdulaziz University , Jeddah , Saudi Arabia
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5
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Chen K, Wang D, Kurgan L. Systematic investigation of sequence and structural motifs that recognize ATP. Comput Biol Chem 2015; 56:131-41. [PMID: 25935117 DOI: 10.1016/j.compbiolchem.2015.04.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 04/05/2015] [Accepted: 04/18/2015] [Indexed: 02/07/2023]
Abstract
Interaction between ATP, a multifunctional and ubiquitous nucleotide, and proteins initializes phosphorylation, polypeptide synthesis and ATP hydrolysis which supplies energy for metabolism. However, current knowledge concerning the mechanisms through which ATP is recognized by proteins is incomplete, scattered, and inaccurate. We systemically investigate sequence and structural motifs of proteins that recognize ATP. We identified three novel motifs and refined the known p-loop and class II aminoacyl-tRNA synthetase motifs. The five motifs define five distinct ATP-protein interaction modes which concern over 5% of known protein structures. We demonstrate that although these motifs share a common GXG tripeptide they recognize ATP through different functional groups. The p-loop motif recognizes ATP through phosphates, class II aminoacyl-tRNA synthetase motif targets adenosine and the other three motifs recognize both phosphates and adenosine. We show that some motifs are shared by different enzyme types. Statistical tests demonstrate that the five sequence motifs are significantly associated with the nucleotide binding proteins. Large-scale test on PDB reveals that about 98% of proteins that include one of the structural motifs are confirmed to bind ATP.
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Affiliation(s)
- Ke Chen
- School of Computer Science and Software Engineering, Tianjin Polytechnic University, Tianjin 300387, China.
| | - Dacheng Wang
- School of Computer Science and Software Engineering, Tianjin Polytechnic University, Tianjin 300387, China
| | - Lukasz Kurgan
- Department of Electrical and Computer Engineering, 2nd floor, ECERF (9107 116 Street), University of Alberta, Edmonton, AB T6G 2V4, Canada
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6
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Waldrop GL, Holden HM, St Maurice M. The enzymes of biotin dependent CO₂ metabolism: what structures reveal about their reaction mechanisms. Protein Sci 2013; 21:1597-619. [PMID: 22969052 DOI: 10.1002/pro.2156] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Biotin is the major cofactor involved in carbon dioxide metabolism. Indeed, biotin-dependent enzymes are ubiquitous in nature and are involved in a myriad of metabolic processes including fatty acid synthesis and gluconeogenesis. The cofactor, itself, is composed of a ureido ring, a tetrahydrothiophene ring, and a valeric acid side chain. It is the ureido ring that functions as the CO₂ carrier. A complete understanding of biotin-dependent enzymes is critically important for translational research in light of the fact that some of these enzymes serve as targets for anti-obesity agents, antibiotics, and herbicides. Prior to 1990, however, there was a dearth of information regarding the molecular architectures of biotin-dependent enzymes. In recent years there has been an explosion in the number of three-dimensional structures reported for these proteins. Here we review our current understanding of the structures and functions of biotin-dependent enzymes. In addition, we provide a critical analysis of what these structures have and have not revealed about biotin-dependent catalysis.
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Affiliation(s)
- Grover L Waldrop
- Division of Biochemistry and Molecular Biology, Louisiana State University, Baton Rouge, Louisiana 70803, USA.
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7
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Fawaz MV, Topper M, Firestine SM. The ATP-grasp enzymes. Bioorg Chem 2011; 39:185-91. [PMID: 21920581 PMCID: PMC3243065 DOI: 10.1016/j.bioorg.2011.08.004] [Citation(s) in RCA: 130] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Revised: 08/12/2011] [Accepted: 08/13/2011] [Indexed: 12/17/2022]
Abstract
The ATP-grasp enzymes consist of a superfamily of 21 proteins that contain an atypical ATP-binding site, called the ATP-grasp fold. The ATP-grasp fold is comprised of two α+β domains that "grasp" a molecule of ATP between them and members of the family typically have an overall structural design containing three common conserved focal domains. The founding members of the family consist of biotin carboxylase, d-ala-d-ala ligase and glutathione synthetase, all of which catalyze the ATP-assisted reaction of a carboxylic acid with a nucleophile via the formation of an acylphosphate intermediate. While most members of the superfamily follow this mechanistic pathway, studies have demonstrated that two enzymes catalyze only the phosphoryl transfer step and thus are kinases instead of ligases. Members of the ATP-grasp superfamily are found in several metabolic pathways including de novo purine biosynthesis, gluconeogenesis, and fatty acid synthesis. Given the critical nature of these enzymes, researchers have actively sought the development of potent inhibitors of several members of the superfamily as antibacterial and anti-obseity agents. In this review, we will discuss the structure, function, mechanism, and inhibition of the ATP-grasp enzymes.
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Affiliation(s)
| | | | - Steven M. Firestine
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI 48201
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8
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The role of the C-terminal region of cyanophycin synthetase from Nostoc ellipsosporum NE1 in its enzymatic activity and thermostability: a key function of Glu(856). BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2008; 1794:42-9. [PMID: 18977318 DOI: 10.1016/j.bbapap.2008.09.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2008] [Revised: 09/11/2008] [Accepted: 09/25/2008] [Indexed: 11/21/2022]
Abstract
The biosynthesis of cyanophycin granule polypeptides is catalyzed by cyanophycin synthetase, CphA. In this study, the role of the C-terminal region of CphA from Nostoc ellipsosporum NE1, CphA(NE1), was analyzed using a tailor-made C-terminus truncated library. The expression level of truncated CphA(NE1) in E. coli depended on the stop codons that were used. The expression vector that had the amber stop codon TAG produced more than twice amount of CphA(NE1) as a vector that contained the ochre codon TAA. CphA(NE1DeltaC45), which was truncated up to 45 amino acids at its C-terminus, retained full enzymatic activity and produced polymers. However, the removal of one additional amino acid, Glu(856), resulted in complete inactivation of CphA(NE1DeltaC46). Replacement of Glu(856) by valine or alanine confirmed the importance of this residue for the activity of CphA(NE1), as it resulted in the complete inactivation of the enzyme. In addition, thermostability analysis revealed a dramatic decrease in the thermostability of CphA(NE1) after removal of the region from Leu(867) to Leu(870). The gel filtration analysis showed that CphA(NE1Delta46C) still formed a dimer form even its enzyme activity was lost completely. These results suggest that Glu(856) is critical for CphA(NE1) catalytic activity and that the predicted alpha-helical region that ranges from Val(858) to Leu(870) is important for the thermostability of the enzyme.
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9
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Füser G, Steinbüchel A. Analysis of genome sequences for genes of cyanophycin metabolism: identifying putative cyanophycin metabolizing prokaryotes. Macromol Biosci 2007; 7:278-96. [PMID: 17390395 DOI: 10.1002/mabi.200600207] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
CGP, a copolymer of aspartate and arginine, serves as a storage compound for nitrogen, carbon and energy in many cyanobacteria. Analysis of available genome sequences from prokaryotes identified ORFs putatively encoding proteins of high similarity to known cyanophycin synthetases and cyanophycinases from cyanobacteria in various strains of bacteria belonging to different phylogenetic taxa and not closely related to cyanobacteria. Genes of CGP metabolism occur in a wide range of bacteria exhibiting diverse metabolic capabilities, including aerobic and anaerobic respiration, fermentation, phototrophy and chemolithoautotrophy. This study identified different groups of cyanophycin synthetases and cyanophycinases, respectively, and proposes a collective terminology for the putative genes and enzymes of cyanophycin metabolism. Among 570 different microbial strains, whose genomes have been partially or completely sequenced and are publicly accessible, we identified 44 prokaryotes which possess a cyanophycin synthetase and are putatively able to synthesize CGP. From these, 31 prokaryotes harbor also a cyanophycinase enabling them to degrade CGP to dipeptides. From the latter, 24 strains possess in addition a dipeptidase necessary to hydrolyze beta-Asp-Arg dipeptides, thereby enabling them to completely utilize CGP. Therefore, CGP seems to have a much wider distribution among prokaryotes than previously recognized. Genes putatively encoding cyanophycin synthetase homologues were not identified in the genomes of Eukarya and Archaea and are therefore obviously only occurring in Eubacteria. In addition, the outcome of this detailed in silico analysis proposes to distinguish 10 different groups of cyanophycin synthetases.
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Affiliation(s)
- Gregor Füser
- Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 3, Münster, Germany
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10
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Brautigam CA, Chelliah Y, Deisenhofer J. Tetramerization and ATP binding by a protein comprising the A, B, and C domains of rat synapsin I. J Biol Chem 2003; 279:11948-56. [PMID: 14688264 DOI: 10.1074/jbc.m312015200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Synapsins are multidomain proteins that are critical for regulating neurotransmitter release in vertebrates. In the present study, two crystal structures of the C domain of rat synapsin I (rSynI-C) in complex with Ca(2+) and ATP reveal that this protein can form a tetramer and that a flexible loop (the "multifunctional loop") contacts bound ATP. Further experiments were carried out on a protein comprising the A, B, and C domains of rat synapsin I (rSynI-ABC). An ATP-stabilized tetramer of rSynI-ABC is observed during velocity sedimentation and size-exclusion chromatographic experiments. These hydrodynamic results also indicate that the A and B domains exist in an extended conformation. Calorimetric measurements of ATP binding to wild-type and mutant rSynI-ABC demonstrate that the multifunctional loop and a cross-tetramer contact are important for ATP binding. The evidence supports a view of synapsin I as an ATP-utilizing, tetrameric protein made up of monomers that have a flexible, extended N terminus.
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Affiliation(s)
- Chad A Brautigam
- Howard Hughes Medical Institute and the Department of Biochemistry, The University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390-9050, USA
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11
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Berg H, Ziegler K, Piotukh K, Baier K, Lockau W, Volkmer-Engert R. Biosynthesis of the cyanobacterial reserve polymer multi-L-arginyl-poly-L-aspartic acid (cyanophycin): mechanism of the cyanophycin synthetase reaction studied with synthetic primers. EUROPEAN JOURNAL OF BIOCHEMISTRY 2000; 267:5561-70. [PMID: 10951215 DOI: 10.1046/j.1432-1327.2000.01622.x] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Biosynthesis of the cyanobacterial nitrogen reserve cyanophycin (multi-L-arginyl-poly-L-aspartic acid) is catalysed by cyanophycin synthetase, an enzyme that consists of a single kind of polypeptide. Efficient synthesis of the polymer requires ATP, the constituent amino acids aspartic acid and arginine, and a primer like cyanophycin. Using synthetic peptide primers, the course of the biosynthetic reaction was studied. The following results were obtained: (a) sequence analysis suggests that cyanophycin synthetase has two ATP-binding sites and hence probably two active sites; (b) the enzyme catalyses the formation of cyanophycin-like polymers of 25-30 kDa apparent molecular mass in vitro; (c) primers are elongated at their C-terminus; (d) the constituent amino acids are incorporated stepwise, in the order aspartic acid followed by arginine, into the growing polymer. A mechanism for the cyanophycin synthetase reaction is proposed; (e) the specificity of the enzyme for its amino-acid substrates was also studied. Glutamic acid cannot replace aspartic acid as the acidic amino acid, whereas lysine can replace arginine but is incorporated into cyanophycin at a much lower rate.
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Affiliation(s)
- H Berg
- Biochemie der Pflanzen, Humboldt-Universität, Berlin, Germany; Universitätsklinikum Charité, Medizinische Immunologie, Berlin, Germany
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12
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Denessiouk KA, Johnson MS. When fold is not important: A common structural framework for adenine and AMP binding in 12 unrelated protein families. Proteins 2000. [DOI: 10.1002/(sici)1097-0134(20000215)38:3<310::aid-prot7>3.0.co;2-t] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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13
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Fraser ME, James MN, Bridger WA, Wolodko WT. A detailed structural description of Escherichia coli succinyl-CoA synthetase. J Mol Biol 1999; 285:1633-53. [PMID: 9917402 DOI: 10.1006/jmbi.1998.2324] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Succinyl-CoA synthetase (SCS) carries out the substrate-level phosphorylation of GDP or ADP in the citric acid cycle. A molecular model of the enzyme from Escherichia coli, crystallized in the presence of CoA, has been refined against data collected to 2.3 A resolution. The crystals are of space group P4322, having unit cell dimensions a=b=98.68 A, c=403.76 A and the data set includes the data measured from 23 crystals. E. coli SCS is an (alphabeta)2-tetramer; there are two copies of each subunit in the asymmetric unit of the crystals. The crystal packing leaves two choices for which pair of alphabeta-dimers form the physiologically relevant tetramer. The copies of the alphabeta-dimer are similar, each having one active site where the phosphorylated histidine residue and the thiol group of CoA are found. CoA is bound in an extended conformation to the nucleotide-binding motif in the N-terminal domain of the alpha-subunit. The phosphoryl group of the phosphorylated histidine residue is positioned at the amino termini of two alpha-helices, one from the C-terminal domain of the alpha-subunit and the other from the C-terminal domain of the beta-subunit. These two domains have similar topologies, despite only 14 % sequence identity. By analogy to other nucleotide-binding proteins, the binding site for the nucleotide may reside in the N-terminal domain of the beta-subunit. If this is so, the catalytic histidine residue would have to move about 35 A to react with the nucleotide.
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Affiliation(s)
- M E Fraser
- Department of Biochemistry, University of Alberta, Canada
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14
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Denessiouk KA, Lehtonen JV, Johnson MS. Enzyme-mononucleotide interactions: three different folds share common structural elements for ATP recognition. Protein Sci 1998; 7:1768-71. [PMID: 10082373 PMCID: PMC2144091 DOI: 10.1002/pro.5560070811] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Three ATP-dependent enzymes with different folds, cAMP-dependent protein kinase, D-Ala:D-Ala ligase and the alpha-subunit of the alpha2beta2 ribonucleotide reductase, have a similar organization of their ATP-binding sites. The most meaningful similarity was found over 23 structurally equivalent residues in each protein and includes three strands each from their beta-sheets, in addition to a connecting loop. The equivalent secondary structure elements in each of these enzymes donate four amino acids forming key hydrogen bonds responsible for the common orientation of the "AMP" moieties of their ATP-ligands. One lysine residue conserved throughout the three families binds the alpha-phosphate in each protein. The common fragments of structure also position some, but not all, of the equivalent residues involved in hydrophobic contacts with the adenine ring. These examples of convergent evolution reinforce the view that different proteins can fold in different ways to produce similar structures locally, and nature can take advantage of these features when structure and function demand it, as shown here for the common mode of ATP-binding by three unrelated proteins.
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Affiliation(s)
- K A Denessiouk
- Department of Biochemistry and Pharmacy, Abo Akademi University, Turku, Finland
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15
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Kazuta Y, Tokunaga E, Aramaki E, Kondo H. Identification of lysine-238 of Escherichia coli biotin carboxylase as an ATP-binding residue. FEBS Lett 1998; 427:377-80. [PMID: 9637261 DOI: 10.1016/s0014-5793(98)00472-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Escherichia coli biotin carboxylase was affinity labeled with adenosine diphosphopyridoxal to identify its ATP binding site. Lysyl endopeptidase digestion of the modified protein, followed by high performance liquid chromatography separation and amino acid sequencing allowed to identify lysine-238 to be the site of modification. Site-directed mutagenesis of this residue into alanine, arginine or glutamine resulted in mutants with much decreased activity. Lysine-238 seems to interact with the gamma-phosphate group of ATP but is not involved in catalysis.
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Affiliation(s)
- Y Kazuta
- Department of Biochemical Engineering and Science, Kyushu Institute of Technology, Iizuka, Japan.
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16
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Galperin MY, Koonin EV. A diverse superfamily of enzymes with ATP-dependent carboxylate-amine/thiol ligase activity. Protein Sci 1997; 6:2639-43. [PMID: 9416615 PMCID: PMC2143612 DOI: 10.1002/pro.5560061218] [Citation(s) in RCA: 209] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The recently developed PSI-BLAST method for sequence database search and methods for motif analysis were used to define and expand a superfamily of enzymes with an unusual nucleotide-binding fold, referred to as palmate, or ATP-grasp fold. In addition to D-alanine-D-alanine ligase, glutathione synthetase, biotin carboxylase, and carbamoyl phosphate synthetase, enzymes with known three-dimensional structures, the ATP-grasp domain is predicted in the ribosomal protein S6 modification enzyme (RimK), urea amidolyase, tubulin-tyrosine ligase, and three enzymes of purine biosynthesis. All these enzymes possess ATP-dependent carboxylate-amine ligase activity, and their catalytic mechanisms are likely to include acylphosphate intermediates. The ATP-grasp superfamily also includes succinate-CoA ligase (both ADP-forming and GDP-forming variants), malate-CoA ligase, and ATP-citrate lyase, enzymes with a carboxylate-thiol ligase activity, and several uncharacterized proteins. These findings significantly extend the variety of the substrates of ATP-grasp enzymes and the range of biochemical pathways in which they are involved, and demonstrate the complementarity between structural comparison and powerful methods for sequence analysis.
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Affiliation(s)
- M Y Galperin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland 20894, USA.
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Ladurner AG, Fersht AR. Glutamine, alanine or glycine repeats inserted into the loop of a protein have minimal effects on stability and folding rates. J Mol Biol 1997; 273:330-7. [PMID: 9367765 DOI: 10.1006/jmbi.1997.1304] [Citation(s) in RCA: 103] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Natural proteins can contain flexible regions in their polypeptide chain. We have investigated the effects of glycine, alanine and glutamine repeats on the stability and folding of a protein by inserting stretches of 7 to 13 residues into a suitable position in a model system, the chymotrypsin inhibitor-2 (CI2). This folds by residues (1-40) docking with residues (41-64) to form a folding nucleus. The peptides GQ4GM, GQ6GM, GQ8GM, GQ10GM, GA2SA4SA2GM and G3SG4SG3M were inserted after residue 40. The stability of the mutant proteins changes only weakly with chain length and nature of insertion, suggesting that the presence of unstructured polypeptide chains in a protein does not have a great energetic penalty. This has implications in catalysis, for example, where floppy regions have been noted in active sites, and in DNA transcription where activators, transcription factors and intermediary proteins all show long repeats of glycine/serine and/or glutamine, which are thought to be important for function. We find that the rate of folding is very insensitive to the length of the linker. The changes in rate are close to those predicted from polymer theory for the loss of configuration entropy on closing a loop. This implies that all the diffusion steps are relatively rapid.
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Affiliation(s)
- A G Ladurner
- MRC Cambridge Centre for Protein Engineering, MRC Centre, UK
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Fan C, Park IS, Walsh CT, Knox JR. D-alanine:D-alanine ligase: phosphonate and phosphinate intermediates with wild type and the Y216F mutant. Biochemistry 1997; 36:2531-8. [PMID: 9054558 DOI: 10.1021/bi962431t] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The crystallographic structure of the D-alanine:D-alanine ligase of the ddlB gene of Escherichia coli complexed with a D-Ala-D-alpha-hydroxybutyrate phosphonate and the structure of the Y216F mutant ligase complexed with a D-Ala-D-Ala phosphinate have been determined to 2.2 and 1.9 A resolution, respectively, and refined to R factors of 0.156 and 0.158. In each complex the inhibitor has reacted with ATP to produce ADP and a tight-binding phosphorylated transition state intermediate. Comparison of these two structures with the known crystal structure of the phosphinate intermediate of the wild-type ligase shows no major conformational changes, but B factors indicate differences in mobility of loops covering the binding site. The weaker inhibition of the Y216F mutant by both inhibitors is thought to be due in part to the loss of an interloop hydrogen bond. A similar mechanism may account for poor inhibition of VanA, the homologous D-Ala:D-lactate ligase produced by vancomycin-resistant enterococci.
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Affiliation(s)
- C Fan
- Department of Molecular and Cell Biology, The University of Connecticut, Storrs 06269-3125, USA
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Tanaka T, Nishioka T, Oda J. Nicked multifunctional loop of glutathione synthetase still protects the catalytic intermediate. Arch Biochem Biophys 1997; 339:151-6. [PMID: 9056244 DOI: 10.1006/abbi.1996.9821] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
A derivative of glutathione synthetase (GSHase) with the multifunctional loop cleaved (nicked GSHase) was compared to both a deletion mutant of the loop (loopless GSHase) and wild-type with the intact loop (wild-type GSHase). The loop had been shown to be in a closed state in order to protect a catalytic intermediate and accelerate the reaction. Data indicated that cleavage of the loop resulted in a drastic decrease in glutathione synthetic activity which was similar to the results for the loop deletion. Kinetic analyses indicated that the manipulations of the loop impaired the substrate affinity, especially for glycine, and also catalytic efficiency. The nicked loop did not accelerate the reaction as fast as the intact loop; however, the catalytic intermediate was protected from hydrolysis by the cleaved loop as effectively as by the intact loop. These results suggest that the fragmental loop assumed the closed state. High concentrations of ATP showed some inhibitory effects on wild-type GSHase, while both nicked and loopless GSHase were not inhibited, indicating that the fragments of the nicked loop functioned independently. In conclusion, it is postulated that the two fragments of the nicked loop independently assumed the closed state to protect the catalytic intermediate and have lost the ability to accelerate glutathione synthesis.
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Affiliation(s)
- T Tanaka
- Institute for Chemical Research, Kyoto University, Japan
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Fukui T, Tanizawa K. Synthesis and application of pyridoxal polyphosphoryl derivatives as active-site probes for nucleotide-binding enzymes. Methods Enzymol 1997; 280:41-50. [PMID: 9211303 DOI: 10.1016/s0076-6879(97)80099-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- T Fukui
- Institute of Scientific and Industrial Research, Osaka University, Japan
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Abstract
The structural classification of proteins reveals that it is already more likely to find that a new protein structure has similarity to another structure than to find that it has a new fold. Reviewed here are those new superfamilies that include proteins of general interest: Sonic hedgehog, macrophage migration inhibitory factor, nuclear transport factor-2, double stranded RNA binding domain, GroES, the proteasome, new ATP-hydrolyzing ligases and flavoproteins.
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Affiliation(s)
- A G Murzin
- Centre for Protein Engineering, Medical Research Council Centre, Cambridge, UK.
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22
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Negishi M, Uno T, Honkakoski P, Sueyoshi T, Darden TA, Pedersen LP. The roles of individual amino acids in altering substrate specificity of the P450 2a4/2a5 enzymes. Biochimie 1996; 78:685-94. [PMID: 9010596 DOI: 10.1016/s0300-9084(97)82525-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
A single amino acid substitution is sufficient to alter substrate specificity of P450 enzymes. Mouse P450 2a5, for example, has its substrate specificity converted from coumarin 7- to testosterone 15 alpha-hydroxylase activity by the substitution of Phe at position 209 to Leu. Furthermore, placing Asn at this position confers a novel corticosterone 15 alpha-hydroxylase activity to this P450. Recent site-directed mutational studies show the presence of the topologically common residues, each of which can determine the specificities of various mammalian P450s. For instance, residue 209 (in 2a5) corresponds to a residue at position 206 in rat P4502B1 that regulates its steroid hydroxylase activity. High substrate specificity often observed in an individual P450, therefore, can be determined and altered by the identities of a few critical residues. The structural flexibility of the substrate-heme pocket may also provide P450 enzymes with the ability to display a broad range of substrate specificities. Understanding the underlying principles whereby the flexible pocket determines P450 activities may lead us to the prediction of P450 activities based on the identities of key amino acid residues.
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Affiliation(s)
- M Negishi
- Pharmacogenetics Section, National Institute of Environmental Health Sciences, National Institute of Health, Research Triangle Park, NC 27709, USA
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