Aggregation propensities of superoxide dismutase G93 hotspot mutants mirror ALS clinical phenotypes

Proceedings of the National Academy of Sciences of the United States of America

Volumn 111, Issue 43, 2014, Pages E4568-E4576

  Pratt, Ashley J ^a,b   Shina, David S ^a,b   Merz, Gregory E ^a,b   Rambo, Robert P ^c   Lancaster, W Andrew ^c   Dyer, Kevin N ^c   Borbat, Peter P ^d   Poole, Farris L ^c   Adams, Michael W W ^c   Freed, Jack H ^d   Crane, Brian R ^b   Tainera, John A ^a,b   Getzoff, Elizabeth D ^a  

^a SCRIPPS RESEARCH INSTITUTE   (United States)

^b LAWRENCE BERKELEY NATIONAL LABORATORY   (United States)

^c Physical Biosciences Division Lawrence Berkeley National Laboratory ^*  (United States)

^d UNIVERSITY OF GEORGIA   (United States)

Author keywords

Esr spectroscopy; Lou gehrig's disease; Protein aggregation; Protein conformation; Small angle x ray scattering

Indexed keywords

COPPER; EDETIC ACID; MUTANT PROTEIN; SUPEROXIDE DISMUTASE; ACID; COPPER ZINC SUPEROXIDE DISMUTASE; PROTECTIVE AGENT; SOLUTION AND SOLUBILITY;

AMYOTROPHIC LATERAL SCLEROSIS; ARTICLE; CONTROLLED STUDY; COPPER DEFICIENCY; ELECTRON SPIN RESONANCE; ENZYME ANALYSIS; HUMAN; IN VITRO STUDY; LIGHT SCATTERING; METAL BINDING; PARTICLE SIZE; PH; PHENOTYPE; PROTEIN AGGREGATION; PROTEIN ANALYSIS; PROTEIN CONFORMATION; STOICHIOMETRY; X RAY CRYSTALLOGRAPHY; CHEMICAL STRUCTURE; CHEMISTRY; ENZYMOLOGY; GENETICS; METABOLISM; MUTATION; PATHOLOGY; PROTEINOSIS; SMALL ANGLE SCATTERING; SOLUTION AND SOLUBILITY;

ACIDS; AMYOTROPHIC LATERAL SCLEROSIS; COPPER; CRYSTALLOGRAPHY, X-RAY; EDETIC ACID; HUMANS; MODELS, MOLECULAR; MUTANT PROTEINS; MUTATION; PHENOTYPE; PROTECTIVE AGENTS; PROTEIN AGGREGATION, PATHOLOGICAL; SCATTERING, SMALL ANGLE; SOLUTIONS; SUPEROXIDE DISMUTASE;

EID: 84908577781     PISSN: 00278424     EISSN: 10916490     Source Type: Journal    
DOI: 10.1073/pnas.1308531111     Document Type: Article

References (109)

1. Pratt AJ, Getzoff ED, Perry JJ (2012) Amyotrophic lateral sclerosis: Update and new developments. Degener Neurol Neuromuscul Dis 2012(2):1-14.
2. Deng HX, et al. (1993) Amyotrophic lateral sclerosis and structural defects in Cu,Zn superoxide dismutase. Science 261(5124):1047-1051.
3. Rosen DR, et al. (1993) Mutations in Cu/Zn superoxide dismutase gene are associated with familial amyotrophic lateral sclerosis. Nature 362(6415):59-62.
4. Andersen PM (2006) Amyotrophic lateral sclerosis associated with mutations in the CuZn superoxide dismutase gene. Curr Neurol Neurosci Rep 6(1):37-46.
5. Getzoff ED, Tainer JA, Stempien MM, Bell GI, Hallewell RA (1989) Evolution of CuZn superoxide dismutase and the Greek key beta-barrel structural motif. Proteins 5(4):322-336.
6. McCord JM, Fridovich I (1969) Superoxide dismutase. An enzymic function for erythrocuprein (hemocuprein). J Biol Chem 244(22):6049-6055.
7. Perry JJ, Shin DS, Getzoff ED, Tainer JA (2010) The structural biochemistry of the superoxide dismutases. Biochim Biophys Acta 1804(2):245-262.
8. Gurney ME, et al. (1994) Motor neuron degeneration in mice that express a human Cu,Zn superoxide dismutase mutation. Science 264(5166):1772-1775.
9. Kato S, et al. (1996) Familial amyotrophic lateral sclerosis with a two base pair deletion in superoxide dismutase 1: Gene multisystem degeneration with intracytoplasmic hyaline inclusions in astrocytes. J Neuropathol Exp Neurol 55(10): 1089-1101.
10. Shibata N, et al. (1996) Intense superoxide dismutase-1 immunoreactivity in intracytoplasmic hyaline inclusions of familial amyotrophic lateral sclerosis with posterior column involvement. J Neuropathol Exp Neurol 55(4):481-490.
11. Sasaki S, et al. (2005) Ultrastructural study of aggregates in the spinal cord of transgenic mice with a G93A mutant SOD1 gene. Acta Neuropathol 109(3):247-255.
12. Bruijn LI, et al. (1997) ALS-linked SOD1 mutant G85R mediates damage to astrocytes and promotes rapidly progressive disease with SOD1-containing inclusions. Neuron 18(2):327-338.
13. Mulder DW, Kurland LT, Offord KP, Beard CM (1986) Familial adult motor neuron disease: Amyotrophic lateral sclerosis. Neurology 36(4):511-517.
14. Wang Q, Johnson JL, Agar NY, Agar JN (2008) Protein aggregation and protein instability govern familial amyotrophic lateral sclerosis patient survival. PLoS Biol 6(7):e170.
15. Andersen PM, et al. (2011) European Handbook of Neurological Management, eds Gilhus NE, Barnes MP, Brainin M (Wiley-Blackwell, Oxford), pp 283-310.
16. Beckman JS, Carson M, Smith CD, Koppenol WH (1993) ALS, SOD and peroxynitrite. Nature 364(6438):584.
17. Wiedau-Pazos M, et al. (1996) Altered reactivity of superoxide dismutase in familial amyotrophic lateral sclerosis. Science 271(5248):515-518.
18. Zhang H, Joseph J, Gurney M, Becker D, Kalyanaraman B (2002) Bicarbonate enhances peroxidase activity of Cu,Zn-superoxide dismutase. Role of carbonate anion radical and scavenging of carbonate anion radical by metalloporphyrin antioxidant enzyme mimetics. J Biol Chem 277(2):1013-1020.
19. Yim MB, et al. (1996) A gain-of-function of an amyotrophic lateral sclerosis-associated Cu,Zn-superoxide dismutase mutant: An enhancement of free radical formation due to a decrease in Km for hydrogen peroxide. Proc Natl Acad Sci USA 93(12): 5709-5714.
20. DiDonato M, et al. (2003) ALS mutants of human superoxide dismutase form fibrous aggregates via framework destabilization. J Mol Biol 332(3):601-615.
21. Johnston JA, Dalton MJ, Gurney ME, Kopito RR (2000) Formation of high molecular weight complexes of mutant Cu, Zn-superoxide dismutase in a mouse model for familial amyotrophic lateral sclerosis. Proc Natl Acad Sci USA 97(23):12571-12576.
22. Bruijn LI, et al. (1998) Aggregation and motor neuron toxicity of an ALS-linked SOD1 mutant independent from wild-type SOD1. Science 281(5384):1851-1854.
23. Stathopulos PB, et al. (2003) Cu/Zn superoxide dismutase mutants associated with amyotrophic lateral sclerosis show enhanced formation of aggregates in vitro. Proc Natl Acad Sci USA 100(12):7021-7026.
24. McRee DE, et al. (1990) Changes in crystallographic structure and thermostability of a Cu,Zn superoxide dismutase mutant resulting from the removal of a buried cysteine. J Biol Chem 265(24):14234-14241.
25. Shin DS, et al. (2009) Superoxide dismutase from the eukaryotic thermophile Alvinella pompejana: Structures, stability, mechanism, and insights into amyotrophic lateral sclerosis. J Mol Biol 385(5):1534-1555.
26. Shin DS, Pratt AJ, Getzoff ED, Perry JJ (2011) Advanced Understanding of Neurodegenerative Diseases, ed Chang RC-C (InTech, Rijeka, Croatia), pp 417-442.
27. Furukawa Y, Fu R, Deng HX, Siddique T, O'Halloran TV (2006) Disulfide cross-linked protein represents a significant fraction of ALS-associated Cu, Zn-superoxide dismutase aggregates in spinal cords of model mice. Proc Natl Acad Sci USA 103(18): 7148-7153.
28. Banci L, et al. (2009) Structural and dynamic aspects related to oligomerization of apo SOD1 and its mutants. Proc Natl Acad Sci USA 106(17):6980-6985.
29. Chen X, et al. (2012) Oxidative modification of cysteine 111 promotes disulfide bondindependent aggregation of SOD1. Neurochem Res 37(4):835-845.
30. Bosco DA, et al. (2010) Wild-type and mutant SOD1 share an aberrant conformation and a common pathogenic pathway in ALS. Nat Neurosci 13(11):1396-1403.
31. Karch CM, Borchelt DR (2008) A limited role for disulfide cross-linking in the aggregation of mutant SOD1 linked to familial amyotrophic lateral sclerosis. J Biol Chem 283(20):13528-13537.
32. Guareschi S, et al. (2012) An over-oxidized form of superoxide dismutase found in sporadic amyotrophic lateral sclerosis with bulbar onset shares a toxic mechanism with mutant SOD1. Proc Natl Acad Sci USA 109(13):5074-5079.
33. Banci L, et al. (2007) Metal-free superoxide dismutase forms soluble oligomers under physiological conditions: A possible general mechanism for familial ALS. Proc Natl Acad Sci USA 104(27):11263-11267.
34. Parge HE, Hallewell RA, Tainer JA (1992) Atomic structures of wild-type and thermostable mutant recombinant human Cu,Zn superoxide dismutase. Proc Natl Acad Sci USA 89(13):6109-6113.
35. Hallewell RA, et al. (1991) Thermostabilization of recombinant human and bovine CuZn superoxide dismutases by replacement of free cysteines. Biochem Biophys Res Commun 181(1):474-480.
36. Lepock JR, Frey HE, Hallewell RA (1990) Contribution of conformational stability and reversibility of unfolding to the increased thermostability of human and bovine superoxide dismutase mutated at free cysteines. J Biol Chem 265(35):21612-21618.
37. Nakamura A, et al. (2012) Marked intrafamilial phenotypic variation in a family with SOD1 C111Y mutation. Amyotroph Lateral Scler 13(5):479-486.
38. Wang Z, et al. (2014) Identification of a novel missense (C7W) mutation of SOD1 in a large familial amyotrophic lateral sclerosis pedigree. Neurobiol Aging 35(3):725. e11-725.e15.
39. Roberts BR, et al. (2007) Structural characterization of zinc-deficient human superoxide dismutase and implications for ALS. J Mol Biol 373(4):877-890.
40. Forman HJ, Fridovich I (1973) On the stability of bovine superoxide dismutase. The effects of metals. J Biol Chem 248(8):2645-2649.
41. Culotta VC, Yang M, O'Halloran TV (2006) Activation of superoxide dismutases: Putting the metal to the pedal. Biochim Biophys Acta 1763(7):747-758.
42. Banci L, Bertini I, Cantini F, D'Onofrio M, Viezzoli MS (2002) Structure and dynamics of copper-free SOD: The protein before binding copper. Protein Sci 11(10):2479-2492.
43. Strange RW, et al. (2003) The structure of holo and metal-deficient wild-type human Cu, Zn superoxide dismutase and its relevance to familial amyotrophic lateral sclerosis. J Mol Biol 328(4):877-891.
44. Strange RW, Yong CW, Smith W, Hasnain SS (2007) Molecular dynamics using atomic-resolution structure reveal structural fluctuations that may lead to polymerization of human Cu-Zn superoxide dismutase. Proc Natl Acad Sci USA 104(24): 10040-10044.
45. Furukawa Y, Kaneko K, Yamanaka K, O'Halloran TV, Nukina N (2008) Complete loss of post-translational modifications triggers fibrillar aggregation of SOD1 in the familial form of amyotrophic lateral sclerosis. J Biol Chem 283(35):24167-24176.
46. Stathopulos PB, et al. (2006) Calorimetric analysis of thermodynamic stability and aggregation for apo and holo amyotrophic lateral sclerosis-associated Gly-93 mutants of superoxide dismutase. J Biol Chem 281(10):6184-6193.
47. Wang J, et al. (2002) Fibrillar inclusions and motor neuron degeneration in transgenic mice expressing superoxide dismutase 1 with a disrupted copper-binding site. Neurobiol Dis 10(2):128-138.
48. Hwang YM, et al. (2010) Nonamyloid aggregates arising from mature copper/zinc superoxide dismutases resemble those observed in amyotrophic lateral sclerosis. J Biol Chem 285(53):41701-41711.
49. Kerman A, et al. (2010) Amyotrophic lateral sclerosis is a non-amyloid disease in which extensive misfolding of SOD1 is unique to the familial form. Acta Neuropathol 119(3):335-344.
50. Ding F, Furukawa Y, Nukina N, Dokholyan NV (2012) Local unfolding of Cu, Zn superoxide dismutase monomer determines the morphology of fibrillar aggregates. J Mol Biol 421(4-5):548-560.
51. Broom HR, Rumfeldt JA, Meiering EM (2014) Many roads lead to Rome? Multiple modes of Cu,Zn superoxide dismutase destabilization, misfolding and aggregation in amyotrophic lateral sclerosis. Essays Biochem 56(1):149-165.
52. Cardoso RMF, et al. (2002) Insights into Lou Gehrig's disease from the structure and instability of the A4V mutant of human Cu,Zn superoxide dismutase. J Mol Biol 324(2):247-256.
53. Tainer JA, Getzoff ED, Beem KM, Richardson JS, Richardson DC (1982) Determination and analysis of the 2 A-structure of copper, zinc superoxide dismutase. J Mol Biol 160(2):181-217.
54. Abel O, Powell JF, Andersen PM, Al-Chalabi A (2012) ALSoD: A user-friendly online bioinformatics tool for amyotrophic lateral sclerosis genetics. Hum Mutat 33(9): 1345-1351.
55. Awano T, et al. (2009) Genome-wide association analysis reveals a SOD1 mutation in canine degenerative myelopathy that resembles amyotrophic lateral sclerosis. Proc Natl Acad Sci USA 106(8):2794-2799.
56. Shelton GD, et al. (2012) Degenerative myelopathy associated with a missense mutation in the superoxide dismutase 1 (SOD1) gene progresses to peripheral neuropathy in Pembroke Welsh corgis and boxers. J Neurol Sci 318(1-2):55-64.
57. Perry JJ, Cotner-Gohara E, Ellenberger T, Tainer JA (2010) Structural dynamics in DNA damage signaling and repair. Curr Opin Struct Biol 20(3):283-294.
58. Rambo RP, Tainer JA (2010) Bridging the solution divide: Comprehensive structural analyses of dynamic RNA, DNA, and protein assemblies by small-angle X-ray scattering. Curr Opin Struct Biol 20(1):128-137.
59. Rambo RP, Tainer JA (2013) Super-resolution in solution X-ray scattering and its applications to structural systems biology. Annu Rev Biophys 42:415-441.
60. Putnam CD, Hammel M, Hura GL, Tainer JA (2007) X-ray solution scattering (SAXS) combined with crystallography and computation: Defining accurate macromolecular structures, conformations and assemblies in solution. Q Rev Biophys 40(3):191-285.
61. Richardson JS, Getzoff ED, Richardson DC (1978) The beta bulge: A common small unit of nonrepetitive protein structure. Proc Natl Acad Sci USA 75(6):2574-2578.
62. Hura GL, et al. (2009) Robust, high-throughput solution structural analyses by small angle X-ray scattering (SAXS). Nat Methods 6(8):606-612.
63. Hammel M, et al. (2011) XRCC4 protein interactions with XRCC4-like factor (XLF) create an extended grooved scaffold for DNA ligation and double strand break repair. J Biol Chem 286(37):32638-32650.
64. Jeffries CM, Whitten AE, Harris SP, Trewhella J (2008) Small-angle X-ray scattering reveals the N-terminal domain organization of cardiac myosin binding protein C. J Mol Biol 377(4):1186-1199.
65. Rambo RP, Tainer JA (2011) Characterizing flexible and intrinsically unstructured biological macromolecules by SAS using the Porod-Debye law. Biopolymers 95(8): 559-571.
66. Hura GL, et al. (2013) Comprehensive macromolecular conformations mapped by quantitative SAXS analyses. Nat Methods 10(6):453-454.
67. Pelikan M, Hura GL, Hammel M (2009) Structure and flexibility within proteins as identified through small angle X-ray scattering. Gen Physiol Biophys 28(2):174-189.
68. Schneidman-Duhovny D, Hammel M, Sali A (2010) FoXS: A web server for rapid computation and fitting of SAXS profiles. Nucleic Acids Res 38(web server issue): W540-W544.
69. Yannone SM, Hartung S, Menon AL, Adams MW, Tainer JA (2012) Metals in biology: Defining metalloproteomes. Curr Opin Biotechnol 23(1):89-95.
70. Cvetkovic A, et al. (2010) Microbial metalloproteomes are largely uncharacterized. Nature 466(7307):779-782.
71. Ahl IM, Lindberg MJ, Tibell LA (2004) Coexpression of yeast copper chaperone (yCCS) and CuZn-superoxide dismutases in Escherichia coli yields protein with high copper contents. Protein Expr Purif 37(2):311-319.
72. Lyons TJ, et al. (2000) The metal binding properties of the zinc site of yeast copperzinc superoxide dismutase: Implications for amyotrophic lateral sclerosis. J Biol Inorg Chem 5(2):189-203.
73. Shibata N, et al. (1994) Cu/Zn superoxide dismutase-like immunoreactivity in Lewy body-like inclusions of sporadic amyotrophic lateral sclerosis. Neurosci Lett 179(1-2): 149-152.
74. Rae TD, Schmidt PJ, Pufahl RA, Culotta VC, O'Halloran TV (1999) Undetectable intracellular free copper: The requirement of a copper chaperone for superoxide dismutase. Science 284(5415):805-808.
75. MaretW, Krezel A (2007) Cellular zinc and redox buffering capacity ofmetallothionein/thionein in health and disease. Mol Med 13(7-8):371-375.
76. Crow JP, Sampson JB, Zhuang Y, Thompson JA, Beckman JS (1997) Decreased zinc affinity of amyotrophic lateral sclerosis-associated superoxide dismutase mutants leads to enhanced catalysis of tyrosine nitration by peroxynitrite. J Neurochem 69(5): 1936-1944.
77. Crapo JD, Oury T, Rabouille C, Slot JW, Chang LY (1992) Copper,zinc superoxide dismutase is primarily a cytosolic protein in human cells. Proc Natl Acad Sci USA 89(21):10405-10409.
78. Yong CW, et al. (2009) Assessment of long-term molecular dynamics calculations with experimental information on protein shape from X-ray scattering-SOD1 as a case study. Chem Phys Lett 481:112-117.
79. Hough MA, et al. (2004) Dimer destabilization in superoxide dismutase may result in disease-causing properties: Structures of motor neuron disease mutants. Proc Natl Acad Sci USA 101(16):5976-5981.
80. Redler RL, Fee L, Fay JM, Caplow M, Dokholyan NV (2014) Non-native soluble oligomers of Cu/Zn superoxide dismutase (SOD1) contain a conformational epitope linked to cytotoxicity in amyotrophic lateral sclerosis (ALS). Biochemistry 53(14): 2423-2432.
81. Rodriguez JA, et al. (2002) Familial amyotrophic lateral sclerosis-associated mutations decrease the thermal stability of distinctly metallated species of human copper/ zinc superoxide dismutase. J Biol Chem 277(18):15932-15937.
82. Lynch SM, Colón W (2006) Dominant role of copper in the kinetic stability of Cu/Zn superoxide dismutase. Biochem Biophys Res Commun 340(2):457-461.
83. Chattopadhyay M, et al. (2008) Initiation and elongation in fibrillation of ALS-linked superoxide dismutase. Proc Natl Acad Sci USA 105(48):18663-18668.
84. Teilum K, et al. (2009) Transient structural distortion of metal-free Cu/Zn superoxide dismutase triggers aberrant oligomerization. Proc Natl Acad Sci USA 106(43): 18273-18278.
85. Lepock JR, Arnold LD, Torrie BH, Andrews B, Kruuv J (1985) Structural analyses of various Cu2+, Zn2+-superoxide dismutases by differential scanning calorimetry and Raman spectroscopy. Arch Biochem Biophys 241(1):243-251.
86. Ip P, Mulligan VK, Chakrabartty A (2011) ALS-causing SOD1 mutations promote production of copper-deficient misfolded species. J Mol Biol 409(5):839-852.
87. Bourassa MW, Brown HH, Borchelt DR, Vogt S, Miller LM (2014) Metal-deficient aggregates and diminished copper found in cells expressing SOD1 mutations that cause ALS. Front Aging Neurosci 6:110.
88. Roberts BR, et al. (2014) Oral treatment with Cu(II)(atsm) increases mutant SOD1 in vivo but protects motor neurons and improves the phenotype of a transgenic mouse model of amyotrophic lateral sclerosis. J Neurosci 34(23):8021-8031.
89. Hayward LJ, et al. (2002) Decreased metallation and activity in subsets of mutant superoxide dismutases associated with familial amyotrophic lateral sclerosis. J Biol Chem 277(18):15923-15931.
90. Goto JJ, et al. (2000) Loss of in vitro metal ion binding specificity in mutant copperzinc superoxide dismutases associated with familial amyotrophic lateral sclerosis. J Biol Chem 275(2):1007-1014.
91. Rothstein JD, et al. (1999) The copper chaperone CCS is abundant in neurons and astrocytes in human and rodent brain. J Neurochem 72(1):422-429.
92. Watanabe M, et al. (2001) Histological evidence of protein aggregation in mutant SOD1 transgenic mice and in amyotrophic lateral sclerosis neural tissues. Neurobiol Dis 8(6):933-941.
93. Kato S, et al. (2001) Copper chaperone for superoxide dismutase co-aggregates with superoxide dismutase 1 (SOD1) in neuronal Lewy body-like hyaline inclusions: An immunohistochemical study on familial amyotrophic lateral sclerosis with SOD1 gene mutation. Acta Neuropathol 102(3):233-238.
94. Son M, et al. (2007) Overexpression of CCS in G93A-SOD1 mice leads to accelerated neurological deficits with severe mitochondrial pathology. Proc Natl Acad Sci USA 104(14):6072-6077.
95. Son M, Fu Q, Puttaparthi K, Matthews CM, Elliott JL (2009) Redox susceptibility of SOD1 mutants is associated with the differential response to CCS over-expression in vivo. Neurobiol Dis 34(1):155-162.
96. Subramaniam JR, et al. (2002) Mutant SOD1 causes motor neuron disease independent of copper chaperone-mediated copper loading. Nat Neurosci 5(4): 301-307.
97. Museth AK, Brorsson AC, Lundqvist M, Tibell LA, Jonsson BH (2009) The ALS-associated mutation G93A in human copper-zinc superoxide dismutase selectively destabilizes the remote metal binding region. Biochemistry 48(37):8817-8829.
98. Merz GE, et al. (2014) Copper-based pulsed dipolar ESR spectroscopy as a probe of protein conformation linked to disease states. Biophys J 107(7):1669-1674.
99. Prudencio M, Hart PJ, Borchelt DR, Andersen PM (2009) Variation in aggregation propensities among ALS-associated variants of SOD1: Correlation to human disease. Hum Mol Genet 18(17):3217-3226.
100. Vassall KA, et al. (2011) Decreased stability and increased formation of soluble aggregates by immature superoxide dismutase do not account for disease severity in ALS. Proc Natl Acad Sci USA 108(6):2210-2215.
101. Byström R, Andersen PM, Gröbner G, Oliveberg M (2010) SOD1 mutations targeting surface hydrogen bonds promote amyotrophic lateral sclerosis without reducing apo-state stability. J Biol Chem 285(25):19544-19552.
102. Mulligan VK, et al. (2012) Early steps in oxidation-induced SOD1 misfolding: Implications for non-amyloid protein aggregation in familial ALS. J Mol Biol 421(4-5): 631-652.
103. Redler RL, et al. (2011) Glutathionylation at Cys-111 induces dissociation of wild type and FALS mutant SOD1 dimers. Biochemistry 50(32):7057-7066.
104. Hallewell RA, et al. (1989) Genetically engineered polymers of human CuZn superoxide dismutase. Biochemistry and serum half-lives. J Biol Chem 264(9):5260-5268.
105. Borgstahl GE, et al. (1996) Human mitochondrial manganese superoxide dismutase polymorphic variant Ile58Thr reduces activity by destabilizing the tetrameric interface. Biochemistry 35(14):4287-4297.
106. Crapo JD, McCord JM, Fridovich I (1978) Preparation and assay of superoxide dismutases. Methods Enzymol 53:382-393.
107. Vaccaro BJ, Menon AL, Lancaster WA, Adams MWW (2009) Current Protocols in Chemical Biology (Wiley, New York).
108. Classen S, et al. (2013) Implementation and performance of SIBYLS: A dual endstation small-angle X-ray scattering and macromolecular crystallography beamline at the Advanced Light Source. J Appl Cryst 46:1-13.
109. Borbat PP, Crepeau RH, Freed JH (1997) Multifrequency two-dimensional Fourier transform ESR: An X/Ku-band spectrometer. J Magn Reson 127(2):155-167.