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Pernil R, Schleiff E. Metalloproteins in the Biology of Heterocysts. Life (Basel) 2019; 9:E32. [PMID: 30987221 PMCID: PMC6616624 DOI: 10.3390/life9020032] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 03/18/2019] [Accepted: 03/28/2019] [Indexed: 12/15/2022] Open
Abstract
Cyanobacteria are photoautotrophic microorganisms present in almost all ecologically niches on Earth. They exist as single-cell or filamentous forms and the latter often contain specialized cells for N₂ fixation known as heterocysts. Heterocysts arise from photosynthetic active vegetative cells by multiple morphological and physiological rearrangements including the absence of O₂ evolution and CO₂ fixation. The key function of this cell type is carried out by the metalloprotein complex known as nitrogenase. Additionally, many other important processes in heterocysts also depend on metalloproteins. This leads to a high metal demand exceeding the one of other bacteria in content and concentration during heterocyst development and in mature heterocysts. This review provides an overview on the current knowledge of the transition metals and metalloproteins required by heterocysts in heterocyst-forming cyanobacteria. It discusses the molecular, physiological, and physicochemical properties of metalloproteins involved in N₂ fixation, H₂ metabolism, electron transport chains, oxidative stress management, storage, energy metabolism, and metabolic networks in the diazotrophic filament. This provides a detailed and comprehensive picture on the heterocyst demands for Fe, Cu, Mo, Ni, Mn, V, and Zn as cofactors for metalloproteins and highlights the importance of such metalloproteins for the biology of cyanobacterial heterocysts.
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Affiliation(s)
- Rafael Pernil
- Institute for Molecular Biosciences, Goethe University Frankfurt, Max-von-Laue-Straβe 9, 60438 Frankfurt am Main, Germany.
| | - Enrico Schleiff
- Institute for Molecular Biosciences, Goethe University Frankfurt, Max-von-Laue-Straβe 9, 60438 Frankfurt am Main, Germany.
- Frankfurt Institute for Advanced Studies, Ruth-Moufang-Straße 1, 60438 Frankfurt am Main, Germany.
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Max-von-Laue-Straβe 15, 60438 Frankfurt am Main, Germany.
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2
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Effects of copper occupancy on the conformational landscape of peptidylglycine α-hydroxylating monooxygenase. Commun Biol 2018; 1:74. [PMID: 30271955 PMCID: PMC6123673 DOI: 10.1038/s42003-018-0082-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 05/25/2018] [Indexed: 11/29/2022] Open
Abstract
The structures of metalloproteins that use redox-active metals for catalysis are usually exquisitely folded in a way that they are prearranged to accept their metal cofactors. Peptidylglycine α-hydroxylating monooxygenase (PHM) is a dicopper enzyme that catalyzes hydroxylation of the α-carbon of glycine-extended peptides for the formation of des-glycine amidated peptides. Here, we present the structures of apo-PHM and of mutants of one of the copper sites (H107A, H108A, and H172A) determined in the presence and absence of citrate. Together, these structures show that the absence of one copper changes the conformational landscape of PHM. In one of these structures, a large interdomain rearrangement brings residues from both copper sites to coordinate a single copper (closed conformation) indicating that full copper occupancy is necessary for locking the catalytically competent conformation (open). These data suggest that in addition to their required participation in catalysis, the redox-active metals play an important structural role. Sweta Maheshwari et al. present X-ray crystal structures of the two-copper enzyme peptidylglycine α-hydroxylating monooxygenase and three inactive mutant forms. They show that full copper occupancy is needed to maintain the catalytically competent (open) conformation of the enzyme.
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3
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Robinson AE, Heffernan JR, Henderson JP. The iron hand of uropathogenic Escherichia coli: the role of transition metal control in virulence. Future Microbiol 2018; 13:745-756. [PMID: 29870278 DOI: 10.2217/fmb-2017-0295] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The role of iron as a critical nutrient in pathogenic bacteria is widely regarded as having driven selection for iron acquisition systems among uropathogenic Escherichia coli (UPEC) isolates. Carriage of multiple transition metal acquisition systems in UPEC suggests that the human urinary tract manipulates metal-ion availability in many ways to resist infection. For siderophore systems in particular, recent studies have identified new roles for siderophore copper binding as well as production of siderophore-like inhibitors of iron uptake by other, competing bacterial species. Among these is a process of nutritional passivation of metal ions, in which uropathogens access these vital nutrients while simultaneously protecting themselves from their toxic potential. Here, we review these new findings within the current understanding of UPEC transition metal acquisition.
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Affiliation(s)
- Anne E Robinson
- Division of Infectious Diseases, Department of Medicine, Department of Molecular Microbiology, Center for Women's Infectious Disease Research, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - James R Heffernan
- Division of Infectious Diseases, Department of Medicine, Department of Molecular Microbiology, Center for Women's Infectious Disease Research, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Jeffrey P Henderson
- Division of Infectious Diseases, Department of Medicine, Department of Molecular Microbiology, Center for Women's Infectious Disease Research, Washington University School of Medicine, St. Louis, MO 63110, USA
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4
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Lambert LJ, Miller MJ, Huber PW. Tetrahydrofuranyl and tetrahydropyranyl protection of amino acid side-chains enables synthesis of a hydroxamate-containing aminoacylated tRNA. Org Biomol Chem 2015; 13:2341-9. [PMID: 25562392 DOI: 10.1039/c4ob02212b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The ability to specifically engineer metal binding sites into target proteins has far-reaching consequences ranging from the development of new biocatalysts and imaging reagents to the production of proteins with increased stability. We report the efficient tRNA-mediated incorporation of the hydroxamate containing amino acid, N(ε)-acetyl-N(ε)-hydroxy-L-lysine, into a transcription factor (TFIIIA). Because this amino acid is compact, hydrophilic, and uncharged at physiological pH, it should have little or no effect on protein folding or solubility. The N(ε)-hydroxy group of the hydroxamate is refractory to photodeprotection and required the identification of reagents for O-protection that are compatible with the synthesis of acylated tRNA. Tetrahydrofuranyl and tetrahydropyranyl O-protecting groups can be removed using mild acid conditions and allowed for an orthogonal protection strategy in which deprotection of the amino acid side chain precedes ligation of an acylated dinucleotide to a truncated suppressor tRNA. These protecting groups will provide a valuable alternative for O-protection, especially in cases where photodeprotection cannot be used.
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Affiliation(s)
- Lester J Lambert
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556.
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5
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Engel N, Bokarev SI, Suljoti E, Garcia-Diez R, Lange KM, Atak K, Golnak R, Kothe A, Dantz M, Kühn O, Aziz EF. Chemical Bonding in Aqueous Ferrocyanide: Experimental and Theoretical X-ray Spectroscopic Study. J Phys Chem B 2014; 118:1555-63. [DOI: 10.1021/jp411782y] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Nicholas Engel
- Joint Ultrafast Dynamics Lab in Solutions and at Interfaces (JULiq) at Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
- Department
of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Sergey I. Bokarev
- Institut
für
Physik, Universität Rostock, Universitätsplatz 3, 18055 Rostock, Germany
| | - Edlira Suljoti
- Joint Ultrafast Dynamics Lab in Solutions and at Interfaces (JULiq) at Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
- Department
of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Raul Garcia-Diez
- Joint Ultrafast Dynamics Lab in Solutions and at Interfaces (JULiq) at Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
- Department
of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Kathrin M. Lange
- Joint Ultrafast Dynamics Lab in Solutions and at Interfaces (JULiq) at Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
- Department
of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Kaan Atak
- Joint Ultrafast Dynamics Lab in Solutions and at Interfaces (JULiq) at Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
- Department
of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Ronny Golnak
- Joint Ultrafast Dynamics Lab in Solutions and at Interfaces (JULiq) at Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
- Department
of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Alexander Kothe
- Joint Ultrafast Dynamics Lab in Solutions and at Interfaces (JULiq) at Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
- Department
of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Marcus Dantz
- Joint Ultrafast Dynamics Lab in Solutions and at Interfaces (JULiq) at Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
- Department
of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Oliver Kühn
- Institut
für
Physik, Universität Rostock, Universitätsplatz 3, 18055 Rostock, Germany
| | - Emad F. Aziz
- Joint Ultrafast Dynamics Lab in Solutions and at Interfaces (JULiq) at Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
- Department
of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
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6
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Yang SQ, Tang L, Yan QJ, Zhou P, Xu HB, Jiang ZQ, Zhang P. Biochemical characteristics and gene cloning of a novel thermostable feruloyl esterase from Chaetomium sp. ACTA ACUST UNITED AC 2013. [DOI: 10.1016/j.molcatb.2013.06.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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7
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Kumar A, Chakravarty H, Bal NC, Balaraju T, Jena N, Misra G, Bal C, Pieroni E, Periasamy M, Sharon A. Identification of calcium binding sites on calsequestrin 1 and their implications for polymerization. MOLECULAR BIOSYSTEMS 2013; 9:1949-57. [PMID: 23629537 PMCID: PMC3719380 DOI: 10.1039/c3mb25588c] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Biophysical studies have shown that each molecule of calsequestrin 1 (CASQ1) can bind about 70-80 Ca(2+) ions. However, the nature of Ca(2+)-binding sites has not yet been fully characterized. In this study, we employed in silico approaches to identify the Ca(2+) binding sites and to understand the molecular basis of CASQ1-Ca(2+) recognition. We built the protein model by extracting the atomic coordinates for the back-to-back dimeric unit from the recently solved hexameric CASQ1 structure (PDB id: ) and adding the missing C-terminal residues (aa350-364). Using this model we performed extensive 30 ns molecular dynamics simulations over a wide range of Ca(2+) concentrations ([Ca(2+)]). Our results show that the Ca(2+)-binding sites on CASQ1 differ both in affinity and geometry. The high affinity Ca(2+)-binding sites share a similar geometry and interestingly, the majority of them were found to be induced by increased [Ca(2+)]. We also found that the system shows maximal Ca(2+)-binding to the CAS (consecutive aspartate stretch at the C-terminus) before the rest of the CASQ1 surface becomes saturated. Simulated data show that the CASQ1 back-to-back stacking is progressively stabilized by the emergence of an increasing number of hydrophobic interactions with increasing [Ca(2+)]. Further, this study shows that the CAS domain assumes a compact structure with an increase in Ca(2+) binding, which suggests that the CAS domain might function as a Ca(2+)-sensor that may be a novel structural motif to sense metal. We propose the term "Dn-motif" for the CAS domain.
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Affiliation(s)
- Amit Kumar
- CRS4, Bioengineering group, Science and Technology Park Polaris, Piscina Manna, 09010 Pula (CA). Italy
| | - Harapriya Chakravarty
- Department of Applied Chemistry, Birla Institute of Technology, Mesra, Ranchi, Jharkhand 835215, India
| | - Naresh C. Bal
- Department of Physiology and Cell Biology, The Ohio State University, College of Medicine, Columbus, OH 43210, United States
| | - Tuniki Balaraju
- Department of Applied Chemistry, Birla Institute of Technology, Mesra, Ranchi, Jharkhand 835215, India
| | - Nivedita Jena
- College of Pharmacy, The Ohio State University, Columbus, OH 43210, United States
| | - Gauri Misra
- Institute of Biotechnology, Amity University, Noida, India
| | - Chandralata Bal
- Department of Applied Chemistry, Birla Institute of Technology, Mesra, Ranchi, Jharkhand 835215, India
| | - Enrico Pieroni
- CRS4, Bioengineering group, Science and Technology Park Polaris, Piscina Manna, 09010 Pula (CA). Italy
| | - Muthu Periasamy
- Department of Physiology and Cell Biology, The Ohio State University, College of Medicine, Columbus, OH 43210, United States
- Davis Heart and Lung Research Institute, Ohio State University, Columbus, Ohio, USA
| | - Ashoke Sharon
- Department of Applied Chemistry, Birla Institute of Technology, Mesra, Ranchi, Jharkhand 835215, India
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8
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Berg JM. Metal-Binding Domains in Nucleic Acid-Binding and Gene-Regulatory Proteins. PROGRESS IN INORGANIC CHEMISTRY 2007. [DOI: 10.1002/9780470166383.ch3] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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9
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Nemirovskiy OV, Gross ML. Determination of calcium binding sites in gas-phase small peptides by tandem mass spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 1998; 9:1020-1028. [PMID: 9755500 DOI: 10.1016/s1044-0305(98)00071-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Low-energy (LE) and high-energy (HE) collisionally activated decompositions (CAD) of calcium/peptide complexes of the form [M - H + Ca]+ and [M + Ca]2+ reflect the site of calcium binding in various gas-phase peptides that are models of the calcium binding site III of rabbit skeletal troponin C. The Ca2+ binding sites involve an aspartic acid, glutamic acid, and asparagine, which are in the metal-binding loops of calcium-binding proteins. Both fast atom bombardment (FAB) and electrospray ionization (ESI) were used to generate the metal/peptide complexes. When submitted to LE CAD, ESI-produced Ca2+/peptide complexes undergo fragmentations that are controlled by Ca2+ binding and provide information on the Ca2+ binding site. The LE CAD spectra are simple, indicating that Ca2+ binding involves specific oxygen ligands including acidic side chains and that only a few low-energy fragmentation channels exist. The HE CAD spectra of FAB-produced Ca2+/peptide complexes are more complex, owing to the introduction of high internal energy into the precursor ion. Interactions of the other alkaline-earth metal ions Mg2+ and Ba2+ with these peptides reveal that the ligand preferences of these metal ions are slightly different than those of Ca2+.
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Affiliation(s)
- O V Nemirovskiy
- Chemistry Department, Washington University, St. Louis, MO 63130, USA
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10
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Karlsson C, Jörnvall H, Höög JO. Zinc binding of alcohol and sorbitol dehydrogenases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1995; 372:397-406. [PMID: 7484403 DOI: 10.1007/978-1-4615-1965-2_47] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- C Karlsson
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
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11
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Stenger JE, Mayr GA, Mann K, Ray S, Anderson ME, Tegtmeyer P. The Quaternary Structures of SV40 Large T Antigen and Tumor Suppressor p53: Analysis by Gel Electrophoresis. GENETIC ENGINEERING 1992; 14:33-48. [PMID: 1368281 DOI: 10.1007/978-1-4615-3424-2_3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/25/2023]
Affiliation(s)
- J E Stenger
- Department of Microbiology, State University of New York, Stony Brook 11794
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12
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Loeber G, Stenger JE, Ray S, Parsons RE, Anderson ME, Tegtmeyer P. The zinc finger region of simian virus 40 large T antigen is needed for hexamer assembly and origin melting. J Virol 1991; 65:3167-74. [PMID: 1851875 PMCID: PMC240973 DOI: 10.1128/jvi.65.6.3167-3174.1991] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Simian virus 40 large T antigen contains a single sequence element with an arrangement of cysteines and histidines that is characteristic of a zinc finger motif. The finger region maps from amino acids 302 through 320 and has the sequence C-302 L K C-305 I K K E Q P S H Y K Y H-317 E K H-320. Previous genetic analysis has shown that the cysteine and histidine sequences and the contiguous S H Y K Y region in the finger are important for DNA replication in vivo. We show here that representative mutations in either of these elements of the finger prevent the assembly of large T antigen into stable hexamers in vitro. These same mutations have a characteristic effect on the interaction of T antigen with the simian virus 40 core origin of replication. The mutant T antigens bind to the central pentanucleotide domain of the core origin but fail to melt the adjacent inverted repeat domain and to untwist the adenine-thymine domain. These defects would prevent the formation of a replication bubble and the initiation of DNA replication. Finger mutations have lesser effects on the helicase function of T antigen and no observable effect on binding of T antigen to the mouse p53 protein. We propose that the zinc finger region contributes to protein-protein interactions essential for the assembly of stable T-antigen hexamers at the origin of replication and that hexamers are needed for subsequent alterations in the structure of origin DNA. We cannot exclude the possibility that the zinc finger region also makes specific contacts with components of origin DNA.
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Affiliation(s)
- G Loeber
- Department of Microbiology, State University of New York, Stony Brook 11794-8621
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13
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Rawls JA, Pusztai R, Green M. Chemical synthesis of human papillomavirus type 16 E7 oncoprotein: autonomous protein domains for induction of cellular DNA synthesis and for trans activation. J Virol 1990; 64:6121-9. [PMID: 2173783 PMCID: PMC248786 DOI: 10.1128/jvi.64.12.6121-6129.1990] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The human papillomavirus type 16 E7 protein belongs to a family of nuclear oncoproteins that share amino acid sequences and functional homology. To localize biochemical activities associated with E7, we chemically synthesized the full-length 98-amino-acid polypeptide and several deletion mutant peptides. We show that the E7 polypeptide is biologically active and possesses at least two functional domains; the first induces cellular DNA synthesis in quiescent rodent cells, and the second trans activates the adenovirus E1A-inducible early E2 promoter and binds zinc. Further, each domain is autonomous and can function on separate peptides. DNA synthesis induction activity maps within the N-terminal portion of the molecule, which contains sequences related to adenovirus E1A conserved domains 1 and 2 required for cell transformation and binding of the retinoblastoma gene product. trans-Activation and Zn-binding activities map within the C-terminal portion of the molecule, a region which contains Cys-X-X-Cys motifs. trans Activation does not require protein synthesis, implying a mechanism that involves interaction with a preexisting cellular factor(s). E7 trans activates the adenovirus E2 promoter but not other E1A-inducible viral promoters, suggesting the possibility that E7 trans activation involves interaction, directly or indirectly, with cellular transcription factor E2F.
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Affiliation(s)
- J A Rawls
- Institute for Molecular Virology, St. Louis University Medical Center, Missouri 63110
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14
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The t(11;14)(p15;q11) in a T-cell acute lymphoblastic leukemia cell line activates multiple transcripts, including Ttg-1, a gene encoding a potential zinc finger protein. Mol Cell Biol 1989. [PMID: 2501659 DOI: 10.1128/mcb.9.5.2124] [Citation(s) in RCA: 141] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Interchromosomal translocations within lymphoid neoplasms frequently involve the antigen receptor genes. We cloned the breakpoints of the t(11;14)(p15;q11) in a CD3-negative T-cell acute lymphoblastic leukemia cell line (RPMI 8402) in order to identify new genes potentially involved in T-cell neoplasia. An extensive comparison of both breakpoints and their germ line counterparts indicated that an inadvertant recombinase-mediated break at chromosome segment 11p15 recombined with the delta T-cell receptor at 14q11. The derivative 11 breakpoint resembles a coding joint in which 11p15 rather than a variable region was introduced 5' to a D delta 1 D delta 2 J delta 1 intermediate rearrangement. Conversely, the derivative 14 breakpoint corresponds to a signal joint between the 5' heptamer-spacer-nonamer recombinational signal of D delta 1 and an isolated heptamer at 11p15. Multiple, apparently distinct transcripts were found flanking both breakpoints of 8402. RNAs of 3.5, 4.4, 1.4, and 8.0 kilobases originating from either side of the derivative 14 breakpoint were highly expressed in 8402 compared with other cells. This suggests that this translocation deregulated multiple genes and provides the opportunity to assess any multifactorial contribution they may have to malignancy. We cloned and sequenced several cDNAs representing the 1.4-kilobase transcript (termed Ttg-1 [T-cell translocation gene 1]) from an 8402 library. The predicted protein of 156 amino acids contained two internal repeats which could potentially form zinc fingers.
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15
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McGuire EA, Hockett RD, Pollock KM, Bartholdi MF, O'Brien SJ, Korsmeyer SJ. The t(11;14)(p15;q11) in a T-cell acute lymphoblastic leukemia cell line activates multiple transcripts, including Ttg-1, a gene encoding a potential zinc finger protein. Mol Cell Biol 1989; 9:2124-32. [PMID: 2501659 PMCID: PMC363006 DOI: 10.1128/mcb.9.5.2124-2132.1989] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Interchromosomal translocations within lymphoid neoplasms frequently involve the antigen receptor genes. We cloned the breakpoints of the t(11;14)(p15;q11) in a CD3-negative T-cell acute lymphoblastic leukemia cell line (RPMI 8402) in order to identify new genes potentially involved in T-cell neoplasia. An extensive comparison of both breakpoints and their germ line counterparts indicated that an inadvertant recombinase-mediated break at chromosome segment 11p15 recombined with the delta T-cell receptor at 14q11. The derivative 11 breakpoint resembles a coding joint in which 11p15 rather than a variable region was introduced 5' to a D delta 1 D delta 2 J delta 1 intermediate rearrangement. Conversely, the derivative 14 breakpoint corresponds to a signal joint between the 5' heptamer-spacer-nonamer recombinational signal of D delta 1 and an isolated heptamer at 11p15. Multiple, apparently distinct transcripts were found flanking both breakpoints of 8402. RNAs of 3.5, 4.4, 1.4, and 8.0 kilobases originating from either side of the derivative 14 breakpoint were highly expressed in 8402 compared with other cells. This suggests that this translocation deregulated multiple genes and provides the opportunity to assess any multifactorial contribution they may have to malignancy. We cloned and sequenced several cDNAs representing the 1.4-kilobase transcript (termed Ttg-1 [T-cell translocation gene 1]) from an 8402 library. The predicted protein of 156 amino acids contained two internal repeats which could potentially form zinc fingers.
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Affiliation(s)
- E A McGuire
- Department of Medicine, Howard Hughes Medical Institute, Washington University, St. Louis, Missouri 63110
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16
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Abstract
Simian virus 40 large T antigen contains a single sequence element with an arrangement of cysteines and histidines that is characteristic of a zinc finger motif. The finger region maps from amino acids 302 through 320 and has the sequence Cys-302LeuLysCys-305IleLysLysGluGlnProSerHisTyrLysTyrHis- 317GluLysHis-320. In a conventional representation, the binding of zinc to the cysteines and histidines at positions 302, 305, 317, and 320 would form two minor loops and one major loop from the intervening amino acids. We made single amino acid substitutions at every position in the finger to identify possible functional elements within the putative metal-binding domain. Amino acids in the zinc finger could be divided into three classes characterized by distinct roles in DNA replication and transformation. Class 1 consisted of amino acids in the two minor loops of the finger and in the amino-terminal part of the major loop. Mutations here did not affect either replication or transformation. Class 2 consisted of the SerHisTyrLysTyr amino acids located in the carboxy terminus of the major loop of the finger. Mutations in this contiguous region reduced replication of the mutant viruses to different degrees. This clustering suggested that the region is an active site important for a specific function in DNA replication. With the exception of a mutation in the histidine at position 313, these mutations had no effect on transformation. Class 3 consisted of the proposed zinc-binding amino acids at positions 302, 305, 317, and 320 and the histidine at position 313 in the major loop of the finger. Mutations in these amino acids abolished the viability of the virus completely and had a distinctive effect on the transforming functions of the protein. Thus, the five cysteines and histidines of class 3 may play an important role in determining the overall structure of the protein. The histidine at position 313 may function both in the active site where it is located and in cooperation with the proposed zinc-binding ligands.
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Affiliation(s)
- G Loeber
- Department of Microbiology, State University of New York, Stony Brook 11794
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17
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Hughes MR, Malloy PJ, Kieback DG, Kesterson RA, Pike JW, Feldman D, O'Malley BW. Point mutations in the human vitamin D receptor gene associated with hypocalcemic rickets. Science 1988; 242:1702-5. [PMID: 2849209 DOI: 10.1126/science.2849209] [Citation(s) in RCA: 283] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Hypocalcemic vitamin D-resistant rickets is a human genetic disease resulting from target organ resistance to the action of 1,25-dihydroxyvitamin D3. Two families with affected children homozygous for this autosomal recessive disorder were studied for abnormalities in the intracellular vitamin D receptor (VDR) and its gene. Although the receptor displays normal binding of 1,25-dihydroxyvitamin D3 hormone, VDR from affected family members has a decreased affinity for DNA. Genomic DNA isolated from these families was subjected to oligonucleotide-primed DNA amplification, and each of the nine exons encoding the receptor protein was sequenced for a genetic mutation. In each family, a different single nucleotide mutation was found in the DNA binding domain of the protein; one family near the tip of the first zinc finger (Gly----Asp) and one at the tip of the second zinc finger (Arg----Gly). The mutant residues were created in vitro by oligonucleotide directed point mutagenesis of wild-type VDR complementary DNA and this cDNA was transfected into COS-1 cells. The produced protein is biochemically indistinguishable from the receptor isolated from patients.
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Affiliation(s)
- M R Hughes
- Department of Cell Biology, Baylor College of Medicine, Houston, TX 77030
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