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Knopman DS, Amieva H, Petersen RC, Chételat G, Holtzman DM, Hyman BT, Nixon RA, Jones DT. Alzheimer disease. Nat Rev Dis Primers 2021; 7:33. [PMID: 33986301 PMCID: PMC8574196 DOI: 10.1038/s41572-021-00269-y] [Citation(s) in RCA: 783] [Impact Index Per Article: 261.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/09/2021] [Indexed: 12/21/2022]
Abstract
Alzheimer disease (AD) is biologically defined by the presence of β-amyloid-containing plaques and tau-containing neurofibrillary tangles. AD is a genetic and sporadic neurodegenerative disease that causes an amnestic cognitive impairment in its prototypical presentation and non-amnestic cognitive impairment in its less common variants. AD is a common cause of cognitive impairment acquired in midlife and late-life but its clinical impact is modified by other neurodegenerative and cerebrovascular conditions. This Primer conceives of AD biology as the brain disorder that results from a complex interplay of loss of synaptic homeostasis and dysfunction in the highly interrelated endosomal/lysosomal clearance pathways in which the precursors, aggregated species and post-translationally modified products of Aβ and tau play important roles. Therapeutic endeavours are still struggling to find targets within this framework that substantially change the clinical course in persons with AD.
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Affiliation(s)
| | - Helene Amieva
- Inserm U1219 Bordeaux Population Health Center, University of Bordeaux, Bordeaux, France
| | | | - Gäel Chételat
- Normandie Univ, UNICAEN, INSERM, U1237, PhIND "Physiopathology and Imaging of Neurological Disorders", Institut Blood and Brain @ Caen-Normandie, Cyceron, Caen, France
| | - David M Holtzman
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA
| | - Bradley T Hyman
- Department of Neurology, Massachusetts General Hospital, Boston, MA, USA
| | - Ralph A Nixon
- Departments of Psychiatry and Cell Biology, New York University Langone Medical Center, New York University, New York, NY, USA
- NYU Neuroscience Institute, New York University Langone Medical Center, New York University, New York, NY, USA
| | - David T Jones
- Department of Neurology, Mayo Clinic, Rochester, MN, USA
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Crystallographic structure and functional implications of the nitrogenase molybdenum-iron protein from azotobacter vinelandii. Nature 2015; 360:553-60. [PMID: 25989647 DOI: 10.1038/360553a0] [Citation(s) in RCA: 389] [Impact Index Per Article: 43.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The crystal structure of the nitrogenase molybdenum–iron protein from Azotobacter vinelandii has been determined at 2.7 Å resolution. The α- and β-subunits in this α (2) β (2) tetramer have similar polypeptide folds. The FeMo-cofactor is completely encompassed by the α-subunit, whereas the P-cluster pair occurs at the interface between α- and β-subunits. Structural similarities are apparent between nitrogenase and other electron transfer systems, including hydrogenases and the photosynthetic reaction centre
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Insights into substrate binding at FeMo-cofactor in nitrogenase from the structure of an α-70Ile MoFe protein variant. J Inorg Biochem 2010; 104:385-9. [DOI: 10.1016/j.jinorgbio.2009.11.009] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2009] [Revised: 11/13/2009] [Accepted: 11/17/2009] [Indexed: 11/19/2022]
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Mortenson LE, Seefeldt LC, Morgan TV, Bolin JT. The role of metal clusters and MgATP in nitrogenase catalysis. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 2006; 67:299-374. [PMID: 8322617 DOI: 10.1002/9780470123133.ch4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- L E Mortenson
- Center for Metalloenzyme Studies, University of Georgia, Athens
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Kent HM, Baines M, Gormal C, Smith BE, Buck M. Analysis of site-directed mutations in the α-and β-subunits ofKlebsiella pneumoniaenitrogenase. Mol Microbiol 2006; 4:1497-1504. [DOI: 10.1111/j.1365-2958.1990.tb02060.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Christiansen J, Dean DR, Seefeldt LC. MECHANISTIC FEATURES OF THE MO-CONTAINING NITROGENASE. ANNUAL REVIEW OF PLANT PHYSIOLOGY AND PLANT MOLECULAR BIOLOGY 2001; 52:269-295. [PMID: 11337399 DOI: 10.1146/annurev.arplant.52.1.269] [Citation(s) in RCA: 130] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Nitrogenase is the complex metalloenzyme responsible for biological dinitrogen reduction. This reaction represents the single largest contributor to the reductive portion of the global nitrogen cycle. Recent developments in understanding the mechanism of the Mo-based nitrogenase are reviewed. Topics include how nucleotide binding and hydrolysis are coupled to electron transfer and substrate reduction, how electrons are accumulated and transferred within the MoFe-protein, and how substrates bind and are reduced at the active site metal cluster.
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Affiliation(s)
- Jason Christiansen
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061; e-mail: , Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84332; e-mail:
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Zou L, Guo SY, Davis LC. Using electrophoresis to observe the interaction of nitrogenase with ions. Electrophoresis 2000; 21:2932-9. [PMID: 11001306 DOI: 10.1002/1522-2683(20000801)21:14<2932::aid-elps2932>3.0.co;2-i] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The two protein components of nitrogenase from Klebsiella pneumoniae were shown to interact with metal ions and ADP, altering their electrophoretic mobility in polyacrylamide gel electrophoresis. Both Mg+2 and Mn+2 caused reduced mobility of Fe protein relative to other proteins. The effect was about 50% complete at concentrations around 0.2 mM. Other ions including Fe+2, Ni+2 and Co+2 had no observable effect at levels up to 1 _mM. Both Cd+2 and Zn+2 appeared to interact with the protein; Cd+2 at 0.5 mM dramatically destabilized the protein. The effects of more than a dozen different mutations of the Fe protein on Mg+2 interaction were examined. All mutated proteins appeared to interact with Mg+2 similarly to wild-type. Using relative mobility differences of charge-changed mutants it was estimated that two to three Mg+2 interact with each Fe protein monomer. The MoFe protein also showed interaction with metal ions but the alteration of mobility was much smaller than for the Fe protein because it is larger and less acidic, so that it runs much more slowly than the Fe protein in standard gels. The interaction of ADP with Fe protein was examined in the presence of Mg+2. Increasing ADP partially reversed the mobility decrease observed on Mg+2 binding, and produced a more diffuse protein band indicative of a reaction zone of interconverting conformers. No alteration of MoFe protein mobility was observed with ADP added during electrophoresis.
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Affiliation(s)
- L Zou
- Department of Biochemistry, Kansas State University, Manhatten 66506, USA
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Shen J, Dean DR, Newton WE. Evidence for multiple substrate-reduction sites and distinct inhibitor-binding sites from an altered Azotobacter vinelandii nitrogenase MoFe protein. Biochemistry 1997; 36:4884-94. [PMID: 9125509 DOI: 10.1021/bi9628578] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The arginine-277 residue of the alpha-subunit of the nitrogenase MoFe protein was targeted for substitution because it is (i) a close neighbor of alpha-cysteine-275, which is one of only two residues anchoring the FeMo cofactor to the polypeptide, and (ii) a component of a potential channel for entry/exit of substrates/products and for accepting FeMo cofactor during MoFe-protein maturation. Several of the eight mutant strains constructed were capable of good diazotrophic growth and also contained FeMo cofactor as indicated by its biologically unique S = 3/2 EPR spectrum. These observations indicate that the positively charged alpha-arginine-277 residue is not required for acceptance of the negatively charged FeMo cofactor by the separately synthesized, cofactor-deficient, apo-MoFe protein. The wide range of nitrogen-fixation phenotypes shown by these mutant strains generally correlated well with their C2H2- and proton-reduction activities, which range from 5 to 65% of wild-type activity. One notable exception is the histidine-substituted strain, DJ788 (alpha-277His). This strain, although unable to fix N2 and grow diazotrophically, elaborates an altered alpha-277His MoFe protein that catalyzes the reduction of the alternative substrates, C2H2, HCN, HN3, and protons. These observations are best explained if multiple redox levels are available to the MoFe protein but the alpha-277His MoFe protein is incapable of reaching the more-reduced redox levels required for nitrogen fixation. Under nonsaturating CO concentrations, the alpha-277His MoFe-protein-catalyzed reduction of C2H2 showed sigmoidal kinetics, which is consistent with inhibitor-induced cooperativity among two C2H4-evolving sites and indicates the presence of three sites, which can be simultaneously occupied, on the MoFe protein. Similar kinetics were not observed for alpha-277His MoFe-protein-catalyzed reduction of either HCN or HN3 with nonsaturating CO levels, indicating that these substrates are unlikely to share common binding sites with C2H2. Further, CN- did not induce cooperativity in C2H2 reduction and, therefore, CO and CN- are unlikely to share a common binding site. These changed substrate specificities, reinforced by changes in the FeMo-cofactor-derived S = 3/2 EPR spectrum, clearly indicate the importance of the alpha-277 residue in catalysis and the delicate control exerted on the properties of bound FeMo cofactor by its polypeptide environment.
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Affiliation(s)
- J Shen
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg 24061-0308, USA
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Fisher M, Gokhman I, Pick U, Zamir A. A structurally novel transferrin-like protein accumulates in the plasma membrane of the unicellular green alga Dunaliella salina grown in high salinities. J Biol Chem 1997; 272:1565-70. [PMID: 8999829 DOI: 10.1074/jbc.272.3.1565] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The alga Dunaliella salina is outstanding is its ability to withstand extremely high salinities. To uncover mechanisms underlying salt tolerance, a search was carried out for salt-induced proteins. The level of a plasma membrane 150-kDa protein, p150, was found to increase with rising external salinity (Sadka, A., Himmelhoch, S., and Zamir, A. (1991) Plant Physiol. 95, 822-831). Based on its cDNA-deduced sequence, p150 belongs to the transferrin family of proteins so far identified only in animals. This, to our best knowledge, is the first demonstration of a transferrin-like protein in a photosynthetic organism. Unlike animal transferrins, p150 contains three, rather than two, internal repeats and a COOH-terminal extension including an acidic amino acid cluster. In intact cells p150 is degraded by Pronase, indicating that the protein is extracellularly exposed. The relationship of p150 to iron uptake is supported by the induction of the protein in iron-deficient media and by its radioactive labeling in cells grown with 59Fe. Accumulation of p150 is transcriptionally regulated. It is proposed that p150 acts in iron uptake other than by receptor-mediated endocytosis and that its induction permits the cells to overcome a possible limitation in iron availability under high salinities.
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Affiliation(s)
- M Fisher
- Department of Biochemistry, Weizmann Institute of Science, Rehovot 76100, Israel
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Abstract
Biological nitrogen fixation is catalyzed by the nitrogenase enzyme system which consists of two metalloproteins, the iron (Fe-) protein and the molybdenum-iron (MoFe-) protein. Together, these proteins mediate the ATP-dependent reduction of dinitrogen to ammonia. Recent crystallographic analyses of Fe-protein and MoFe-protein have revealed the polypeptide fold and the structure and organization of the unusual metal centers in nitrogenase. These structure provide a molecular framework for addressing the mechanism of the nitrogenase-catalyzed reaction. General features of the nitrogenase system, including conformational coupling of nucleotide hydrolysis, aspects of the cluster structures, and the general spatial organization of redox centers within the protein subunits, are relevant to a wide range of biochemical systems.
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Affiliation(s)
- J Kim
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena 91125
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Dean DR, Bolin JT, Zheng L. Nitrogenase metalloclusters: structures, organization, and synthesis. J Bacteriol 1993; 175:6737-44. [PMID: 8226614 PMCID: PMC206795 DOI: 10.1128/jb.175.21.6737-6744.1993] [Citation(s) in RCA: 130] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Affiliation(s)
- D R Dean
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg 24061
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Homer MJ, Paustian TD, Shah VK, Roberts GP. The nifY product of Klebsiella pneumoniae is associated with apodinitrogenase and dissociates upon activation with the iron-molybdenum cofactor. J Bacteriol 1993; 175:4907-10. [PMID: 8335644 PMCID: PMC204945 DOI: 10.1128/jb.175.15.4907-4910.1993] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Apodinitrogenase, which lacks the iron-molybdenum cofactor at its active site, is an oligomer that contains an additional protein not found in the active dinitrogenase tetramer. This associated protein in Klebsiella pneumoniae is shown to be the product of the nifY gene. When apodinitrogenase is activated by the addition of the iron-molybdenum cofactor, NifY dissociates from the apodinitrogenase complex. The conditions for this dissociation are described. Finally, there are aspects of the dissociation and insertion process in K. pneumoniae that are different from that in Azotobacter vinelandii.
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Affiliation(s)
- M J Homer
- Department of Bacteriology, University of Wisconsin, Madison 53706
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Rees DC, Chan MK, Kim J. Structure and Function of Nitrogenase. ADVANCES IN INORGANIC CHEMISTRY 1993. [DOI: 10.1016/s0898-8838(08)60182-8] [Citation(s) in RCA: 77] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Govezensky D, Greener T, Segal G, Zamir A. Involvement of GroEL in nif gene regulation and nitrogenase assembly. J Bacteriol 1991; 173:6339-46. [PMID: 1680848 PMCID: PMC208965 DOI: 10.1128/jb.173.20.6339-6346.1991] [Citation(s) in RCA: 63] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Several approaches were used to study the role of GroEL, the prototype chaperonin, in the nitrogen fixation (nif) system. An Escherichia coli groEL mutant transformed with the Klebsiella pneumoniae nif gene cluster accumulated very low to nondetectable levels of nitrogenase components compared with the isogenic wild-type strain or the mutant cotransformed with the wild-type groE operon. In K. pneumoniae, overexpression of the E. coli groE operon markedly accelerated the rate of appearance of the MoFe protein and its constituent polypeptides after the start of derepression. The groEL mutation in E. coli decreased NifA-dependent beta-galactosidase expression from the nifH promoter but did not affect the constitutive expression of nifA from the tet promoter of ntr-controlled expression from the nifLA promoter. The possibility that GroEL is required for the correct folding of NifA was supported by coimmunoprecipitation of NifA with anti-GroEL antibodies. Kinetic analyses of nitrogenase assembly in 35S pulse-chased K. pneumoniae pointed to the existence of high-molecular-weight intermediates in MoFe protein assembly and demonstrated the transient binding of newly synthesized NifH and NifDK to GroEL. Overall, these results indicate that GroEL fulfills both regulatory and structural functions in the nif system.
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Affiliation(s)
- D Govezensky
- Biochemistry Department, Weizmann Institute of Science, Rehovot, Israel
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