Investigation of compound-specific organic-inorganic phosphorus transformation using stable isotope ratios in phosphate

Applied Manure and Nutrient Chemistry for Sustainable Agriculture and Environment

Volumn 9789401788076, Issue , 2014, Pages 267-292

  Jaisi, Deb P ^a   Blake, Ruth E ^b   Liang, Yuhong ^c   Chang, Sae Jung ^b  

^a UNIVERSITY OF DELAWARE   (United States)

^b YALE UNIVERSITY   (United States)

^c MOUNT SINAI SCHOOL OF MEDICINE   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

ECOSYSTEMS; ISOTOPES; SEDIMENTS;

INORGANIC PHOSPHORUS; INORGANICS; LIFE-FORMS; METABOLIC PATHWAYS; ORGANIC/INORGANIC; ORGANICS; P CYCLING; PHOSPHORUS TRANSFORMATIONS; STABLE ISOTOPE RATIOS; UPTAKE MECHANISM;

HYDROLYSIS;

EID: 84921466772     PISSN: None     EISSN: None     Source Type: Book    
DOI: 10.1007/978-94-017-8807-6_13     Document Type: Chapter

References (122)

1. Aber JD, Nadelhoffer KJ, Steudler P, Melillo JM (1989) Nitrogen saturation in northern forest ecosystems. BioScience 39:378-386
2. Admiraal SJ, Herschlag D (1999) Catalysis of phosphoryl transfer from ATP by amine nucleophiles. J Am Chem Soc 121:5837-5845
3. Ammerman JW, Azam F (1985) Bacterial 50-nucleotidase in aquatic ecosystems: a novel mechanism of phosphorus regeneration. Science 227:1338-1340
4. Angert A, Weiner T, Mazeh S, Sternberg M (2012) Soil phosphate stable oxygen isotopes across rainfall and bedrock gradients. Environ Sci Technol 46:2156-2162
5. Ator SW, Brakebill JW, Blomquist JD (2011) Sources, fate, and transport of nitrogen and phosphorus in the Chesapeake Bay watershed: an empirical model. U.S. Geological Survey Scientific Investigations Report 2011-5167, 27pp
6. Baykov AA, Shestakov AS (1992) Two pathways of pyrophosphate hydrolysis and synthesis by yeast inorganic pyrophosphatase. Eur J Biochem 206:463-470
7. Baykov AA, Shestakov AS, Kasho VN, Vener AV, Ivanov AH (1990) Kinetics and thermodynamics of catalysis by the inorganic pyrophosphatase of Escherichia coli in both directions. Eur J Biochem 194:879-887
8. Baykov AA, Kasho VN, Bakuleva NP, Rea PA (1994) Oxygen exchange reactions catalyzed by vacuolar H + -translocating payrophosphatase. FEBS Lett 350:323-327
9. Benitez-Nelson CR (2000) The biogeochemical cycling of phosphorus in marine systems. Earth Sci Rev 51:109-135
10. Blake RE, O'Neil JR, Garcia GA (1997) Oxygen isotope systematics of microbially mediated reactions of phosphate: I. Degradation of organophosphorus compounds. Geochim Cosmochim Acta 61:4411-4422
11. Blake RE, O'Neil JR, Garcia GA (1998a) Enzyme-catalyzed oxygen isotope exchange between inorganic phosphate and water: reaction rates and temperature dependence at 5.7-30 °C. Miner Mag 62:163-164
12. Blake RE, O'Neil JR, Garcia GA (1998b) Effects of microbial activity on the δ18Op of dissolved inorganic phosphate and textural features of synthetic apatites. Am Mineral 83:1516-1531
13. Blake RE, Alt JC, Martini AM (2001) Oxygen isotope ratios of PO4: an inorganic indicator of enzymatic activity and P metabolism and a new biomarker in the search for life. Proc Nat Acad Sci USA 98:2148-2153
14. Blake RE, O'Neil JR, Surkov AV (2005) Biogeochemical cycling of phosphorus: insights from oxygen isotope effects of phosphoenzymes. Am J Sci 305:596-620
15. Blake RE, Chang SJ, Lepland A (2010) Phosphate oxygen isotopic evidence for a temperate and biologically active Archaean ocean. Nature 464:1029-1032
16. Böhlke JK, Denver JM (1995) Combined use of groundwater dating, chemical, and isotopic analyses to resolve the history and fate of nitrate contamination in two agricultural watersheds, Atlantic coastal plain, Maryland. Water Resour Res 31:2319-2339
17. Bourne N, Williams A (1984) Evidence for a single transition state in the transfer of the phosphoryl group (-PO3 2- ) transfer to pyridines from isoquinoline-N-phosphonate. J Am Chem Soc 105:3357-3358
18. Braun AM, Frimmel FH, Haigne J (1986) Singlet oxygen analysis in irradiated surface waters. Int J Environ Anal Chem 27:137-149
19. Breslow R (1993) Kinetics and mechanism in RNA cleavage. Proc Natl Acad Sci U S A 90:1208-1211
20. Bünemann EK, Condron LM (2007) Phosphorus and sulfur cycling in terrestrial ecosystems. In: Marschner P, Rengel Z (eds) Nutrient cycling in terrestrial ecosystems, Soil biology. Springer, Heidelberg
21. Bunton CA, Llewellyn DR, Oldham KG, Vernon CA (1958) The reactions of organic phosphates: the hydrolysis of methyl dihydrogen phosphate. J Chem Soc 3574-3587
22. Cade-Menun BJ, Liu CW, Nunlist R, McColl JG (2002) Soil and litter phosphorus-31 nuclear magnetic resonance spectroscopy: extractants, metals, and phosphorus relaxation times. J Environ Qual 31:457-465
23. Carpenter SR, Caraco NF, Correl DL, Howarth RW, Sharpley AN, Smith VH (1998) Nonpoint pollution of surface waters with phosphorus and nitrogen. Ecol Appl 8:559-568
24. Carreira JA, Vinegla B, Blanes MC, Garcia-Ruiz R (2010) Stable isotopes and changing paradigms on soil nitrogen and carbon biogeochemistry. Ecosistemas 29:14-23
25. Cassano AG, Anderson VE, Harris ME (2004) Understanding the transition states of phosphodiester bond cleavage: insights from heavy atom isotope effects. Biopolymers 73:110-129
26. Chiba H, Kusakabe M, Hirano SI, Matsuo S, Somiya S (1981) Oxygen isotope fractionation factors between anhydrite and water from 100°C to 550°C. Earth Planet Sci Lett 53:55-62
27. Cohn M (1953) A study of oxidative phosphorylation with 18O-labeled inorganic phosphate: J Biol Chem 201:735-750
28. Colman AS, Blake RE, Karl DM, Fogel ML, Turekian KK (2005) Marine phosphate oxygen isotopes and organic matter remineralization in the oceans. Proc Natl Acad Sci U S A 102:13023-13028
29. Cotner JB, Wetzel RG (1992) Uptake of dissolved inorganic and organic phosphorus compounds by phytoplankton and bacterioplankton. Limnol Oceanogr 37:232-243
30. Cox C (2004) Herbicide factsheet-glyphosate. J Pest Reform 24:10-15
31. Davidson EA, Hart SC, Firestone MK (1992) Internal cycling of nitrate in soils of a mature coniferous forest. Ecology 73:1148-1156
32. Dyhrman ST, Ruttenberg KC (2006) Presence and regulation of alkaline phosphatase activity in eukaryotic phytoplankton from the coastal ocean: implications for dissolved organic phosphorus re-mineralization. Limnol Oceanogr 51:1381-1390
33. Dyhrman ST, Benitez-Nelson CR, Orchard ED, Haley ST, Pellechia PJ (2009) A microbial source of phosphonates in oligotrophic marine systems. Nat Geosci 2:696-699
34. Dzombak DA (2011) Nutrient control in large-scale US watersheds: the Chesapeake Bay and Northern Gulf of Mexico. Bridge Nat Acad Eng 41:13-22
35. Ehrlich HL (1996) Geomicrobiology, 3rd edn. Deckker, New York
36. Elsbury KE, Paytan A, Ostrom NE, Kendall C, Young MB, McLaughlin K, Rollog ME, Watson S (2009) Using oxygen isotopes of phosphate to trace phosphorus sources and cycling in Lake Erie. Environ Sci Technol 43:3108-3114
37. Erickson BE (2011) Cleaning the Chesapeake Bay. Chem Eng News 89:10-14
38. Frossard E, Brossard M, Hedley MJ, Metherell A (1995) Reactions controlling the cycling of P in soils. In: Tiessen H (ed) Phosphorus cycling in terrestrial and aquatic ecosystems: a global perspective. SCOPE/Wiley, New York
39. erratana B, Sowa GA, Cleland WW (2000) Characterization of the transition state structures and mechanisms for the isomerization and cleavage reactions of 30m-nitrobenzyl phosphate. J Am Chem Soc 122:12615-12621
40. Goldhammer T, Brunner B, Bernasconi SM, Ferdelman T, Zabel M (2011) Phosphate oxygen isotopes: insights into sedimentary phosphorus cycling from the Benguela upwelling system. Geochim Cosmochim Acta 75:3741-3756
41. Green M, Taube H (1963) Isotopic fractionation in the OH-H2O exchange reaction. J Phys Chem 67:1565-1566
42. Gross A, Nishri A, Angert A (2013) Use of phosphate oxygen isotopes for identifying atmospheric-P sources: a case study at Lake Kinneret. Environ Sci Technol 47:2721-2727
43. Gruau G, Legeas M, Riou C, Gallacier E, Martineau F, Hénina O (2005) The oxygen isotopic composition of dissolved anthropogenic phosphates: a new tool for eutrophication research? Water Res 39:232-238
44. Hart SC, Stark JM, Davidson EA, Firestone MK (1994) Nitrogen mineralization, immobilization, and nitrification. In: Weaver RW, Angle JS, Bottomley PJ, Bezdicek DF, Smith MS, Tabatabai MA, Wollun AG (eds) Method of soil analysis, Part 2. Microbiological and biochemical properties, Soil Science Society of America book series. Soil Science Society of America, Wisconsin, pp 985-1018
45. Harway GW, Keister DL (1981) Energy-linked reactions in photosynthetic bacteria: Pi = HOH oxygen exchange catalyzed by the membrane-bound inorganic pyrophosphatase of Rhodospirillum rubrum. Arch Biochem Biophys 208:426-430
46. Heikinheimo P, Lehtonen J, Baykov A, Lathi R, Cooperman BS, Goldman A (1996) The structural basis for pyrophosphatase catalysis. Structure 4:1491-1508
47. Hengge AC (2002) Isotope effects in the study of phosphoryl and sulfuryl transfer reactions. Acc Chem Res 35:105-112
48. Hengge AC, Tobin AE, Cleland WW (1995) Studies of transition-state structures in phosphoryl transfer reactions of phosphodiesters of p-nitrophenol. J Am Chem Soc 214:5919-5926
49. Herschlag D, Jencks WP (1989) Evidence that metaphosphate monoanion is not an intermediate in solvolysis reactions in aqueous solution. J Am Chem Soc 111:7579-7586
50. Hoering TC, Kennedy JW (1957) The exchange of oxygen between sulfuric acid and water. J Am Chem Soc 79:56-60
51. Hoppe H-G, Ullrich S (1999) Profiles of ectoenzymes in the Indian Ocean: phenomena of phosphatase activity in the mesopelagic zone. Aquat Microb Ecol 19:139-148
52. Jaisi DP (2013) Isotope effects during phosphate transport in packed-bed sediment columns. J Contam Hydrol 154:10-19
53. Jaisi DP, Blake RE (2010) Tracing sources and cycling of phosphorus in Peru Margin sediments using oxygen isotopes in authigenic and detrital phosphates. Geochim Cosmochim Acta 74:3199-3212
54. Jaisi DP, Blake RE, Kukkadapu RK (2010) Fractionation of oxygen isotopes in phosphate during its interactions with iron oxides. Geochim Cosmochim Acta 74:1309-1319
55. Jaisi DP, Kukkadapu RK, Stout LM, Varga T, Blake RE (2011) Biotic and abiotic pathways of phosphorus cycling in minerals and sediments: insights from oxygen isotope ratios in phosphate. Environ Sci Technol 45:6254-6261
56. Johansen HS, Middleboe V, Larsen S (1991) Delabeling of 18O enriched phosphate added to soil as a function of biological activities in the soils. In: Proceedings of the stable isotopes in plant nutrition, soil fertility and environmental studies. IAEA, Vienna, pp 553-559
57. Jong F (2006) Marine eutrophication in perspective. Springer, New York
58. Kasho VN, Baykov AA (1989) Two pathways for phosphate-water oxygen by yeast inorganic pyrophosphatase. Biochem Biophys Res Commun 161:475-480
59. Kemmitt SJ, Lanyon CV, Waite IS, Wen Q, Addiscott TM, Bird NA, O'Donnell AG, Brookes PC (2008) Mineralization of native soil organic matter is not regulated by the size, activity or composition of the soil microbial biomass - a new perspective. Soil Biol Biochem 40:61-73
60. Kendall C (1998) Tracing nitrogen sources and cycles in catchments. In: Kendall C, McDonnell JJ (eds) Isotope tracers in catchment hydrology. Elsevier Science, Amsterdam, pp 519-576
61. Khan SA, Kirby AJ (1970) Reactivity of phosphate esters. Multiple structure-reactivity correlations for reactions of triesters with nucleophiles. J Chem Soc B 1172-1182
62. Kirby AJ, Jencks WP (1965) Reactivity of nucleophilic reagents toward p-nitrophenyl phosphate dianion. J Am Chem Soc 87:3209-3216
63. Kirby AJ, Younas M (1970) The reactivity of phosphate esters. Diester hydrolysis. J Chem Soc 3:510-513
64. Knowles JR (1980) Enzyme-catalyzed phosphoryl transfer reactions. Annu Rev Biochem 49:877-919
65. Kolodny Y, Luz B, Navon O (1983) Oxygen isotope variations in phosphate of biogenic apatites: 1. Fish bone apatite & rechecking the rules of the game. Earth Planet Sci Lett 64:398-404
66. Kolowith LC, Ingall ED, Benner R (2001) Composition and cycling of marine organic phosphorus. Limnol Oceanogr 46:309-320
67. Kumamoto J, Westheimer FH (1955) The hydrolysis of mono- and dibenzyl phosphates. J Am Chem Soc 77:2515-2518
68. Lad C, Williams NH, Wolfendan R (2003) The rate of hydrolysis of phosphomonoester dianions and the exceptional catalytic proficiencies of protein and inositol phosphatase. Proc Natl Acad Sci U S A 100:5607-5610
69. Larsen S, Middelboe V, Johansen HS (1989) The fate of 18O labeled phosphate in soil plantsystems. Plant Soil 117:143-145
70. Lassila JK, Zalatan JG, Herschlag D (2011) Biological phosphoryl-transfer reactions: understanding mechanism and catalysis. Ann Rev Biochem 80:669-702
71. Lecuyer C, Greansjean P, Sheppard MF (1999) Oxygen isotope exchange between dissolved phosphate and water at temperatures <135°C: inorganic versus biological fractionations. Geochim Cosmochim Acta 63:855-862
72. Liang Y, Blake RE (2006a) Oxygen isotope composition of phosphate in organic compounds: isotope effects of extraction methods. Org Geochem 37:1263-1277
73. Liang Y, Blake RE (2006b) Oxygen isotope signature of Pi regeneration from organic compounds by phosphomonoesterases and photooxidation. Geochim Cosmochim Acta 70:3957-3969
74. Liang Y, Blake RE (2007) Oxygen isotope fractionation between apatite and dissolved aqueous phosphate: 20-45 °C. Chem Geol 238:121-133
75. Liang Y, Blake RE (2009) Compound and enzyme-specific phosphodiester hydrolysis mechanisms revealed by delta O-18 of dissolved inorganic phosphate: implications for marine P cycling. Geochim Cosmochim Acta 73:3782-3794
76. Longinelli A, Nuti S (1973a) Revised phosphate-water isotopic temperature scale. Earth Planet Sci Lett 19:373-376
77. Longinelli A, Nuti S (1973b) Oxygen isotope measurements of phosphate from fish teeth and bones. Earth Planet Sci Lett 20:337-340
78. Markel D, Kolodny Y, Luz B, Nishri A (1994) Phosphorus cycling and phosphorus sources in Lake Kineret: tracing by oxygen isotopes in phosphate. Israel J Earth Sci 43:165-178
79. Matte A, Tari LW, Delbaere LJ (1998) How do kinases transfer phosphoryl groups? Structure 6:413-419
80. McKelvie ID (2005) Separation, preconcentration and speciation of organic phosphorus in environmental samples. In: Turner BL, Frossard E, Baldwin DS (eds) Organic phosphorus in the environment. CABI Publishing, London, pp 1-20
81. McLaughlin K, Kendall C, Silva SR, Young M, Paytan A (2006) Phosphate oxygen isotope ratios as a tracer for sources and cycling of phosphate in North San Francisco Bay, California. J Geophys Res Biogeosci 111:3003
82. Melander L, Saunders WH (1980) Reaction rates of isotopic molecules. Wiley, New York
83. Melby ES, Soldat DJ, Barak P (2011) Synthesis and detection of oxygen-18 labeled phosphate. PLoS One 6:e18420
84. Mildvan AS (1979) The role of metals in enzyme-catalyzed substitutions at each phosphorus atom of ATP. Adv Enzymol 49:103-126
85. Mildvan AS (1997) Mechanisms of signaling and related enzymes. Proteins 24:401-416
86. Mishra NC (2002) Nucleases: molecular biology and application. Wiley, New York
87. Mopper K, Kieber DJ (2002) Photochemistry and the cycling of carbon, sulfur, nitrogen, and phosphorus. In: Hansell DA, Carlson CA (eds) Biogeochemistry of marine dissolved organic matter. Academic Press, Amsterdam, pp 455-508
88. Nadelhoffer KJ, Fry B (1994) Nitrogen isotope studies in forest ecosystems. In: Lajtha K, Michener R (eds) Stable isotopes in ecology and environmental science. Blackwell Scientific Publications, Boston, pp 23-44
89. Nausch M, Nausch G (2007) Bioavailable dissolved organic phosphorus and phosphorus use by heterotrophic bacteria. Aquat Biol 1:151-160
90. Nicholson D, Dyhrman S, Chavez F, Paytan A (2006) Alkaline phosphatase activity in the phytoplankton communities of Monterey Bay and San Francisco Bay. Limnol Oceanogr 51:874-883
91. O'Neil JR, Vennemann TW, McKenzie WF (2003) Effects of speciation on equilibrium fractionations and rates of oxygen isotope exchange between (PO4)(aq) and H2O. Geochim Cosmochim Acta 67:3135-3144
92. Oelmann Y, Kreutziger Y, Bol R, Wilcke W (2007) Nitrate leaching in soil: tracing the NO3 sources with the help of stable N and O isotopes. Soil Biol Biochem 39:3024-3033
93. Ohio EPA (2010) Ohio Lake Erie phosphorus task force final report. Ohio Environmental Protection Agency, Columbus, 109pp
94. Paytan A, Luz B, Kolodny Y, Neori A (2002) Biologically mediated oxygen isotope exchange between water and phosphorus. Global Biogeochem Cycles 16:131-137
95. Perry MJ (1972) Alkaline phosphatase activity in Subtropical Central North Pacific waters using a sensitive fluorometric method. Mar Biol 15:113-119
96. RCN-SEES (2012) Coordinating phosphorus research to create a sustainable food system. http://sustainablep.asu.edu/prcn. Accessed on 8/11/2013
97. Redfield AC (1958) The biological control of chemical factors in the environment. Am Sci 46:1-221
98. Sandy EH, Blake RE, Chang SJ, Jun Y, Yub C (2013) Oxygen isotope signature of UV degradation of glyphosate and phosphonoacetate: tracing sources and cycling of phosphonates. J Hazard Mater 260:947-954
99. Sivula T, Salminena A, Parfenyev AN, Pohjanjoki P, Goldman A, Cooperman BS, Baykov A, Lathi R (1999) Evolutionary aspects of inorganic pyrophosphatase. FEBS Lett 454:75-80
100. Smirnova IN, Kasho VN, Volk SE, Ivanov AH, Baykov AA (1995) Rates of elementary steps catalyzed by rat liver cytosolic and mitochondrial inorganic pyrophosphatases in both directions. Arch Biochem Biophys 318:340-348
101. Smucker RA, Kim CK (1991) Chitinase activity in estuarine waters. In: Chrost RJ (ed) Microbial enzymes in aquatic environments. Springer, New York, pp 249-269
102. Suh S, Yee S (2011) Phosphorus use-efficiency of agriculture and food system in the US. Chemosphere 84:806-813
103. Syers JK, Johnson AE, Curtin D (2008) Efficiency of soil and fertilizer phosphorus use: reconciling changing concepts of soil phosphorus behavior with agronomic information. FAO Fertilizer and Plant Nutrition Bulletin, 123 pp
104. Taft JL, Loftus ME, Taylor WR (1977) Phosphate uptake from phosphomonoesters by phytoplankton in the Chesapeake Bay. Limnol Oceanogr 22:1012-1021
105. Tamburini F, Pfahler V, Bunemann EK, Guelland K, Bernasconi SM, Frossard E (2012) Oxygen Isotopes unravel the role of microorganisms in phosphate cycling in soils. Environ Sci Technol 46:5956-5962
106. Tilman D, Fargione J, Wolff B, D'Antonio C, Dobson A, Howath R, Schinder D, Schlesinger WH, Simberloff D, Swackhamer D (2001) Forecasting agriculturally driven global environmental change. Science 292:281-284
107. Tudge AP (1960) A method of analysis of oxygen isotopes in orthophosphate and its use in measurement of paleotemperatures. Geochim Cosmochim Acta 18:81-93
108. van Moorleghem C, De Schutter N, Smolders E, Merckx R (2013) Bioavailability of organic phosphorus to Pseudokirchneriella subcapitata as affected by phosphorus starvation: an isotope dilution study. Water Res 47:3047-3056
109. Vanderzee C, Roevros N, Chou L (2007) Phosphorus speciation, transformation and retention in the Scheldt estuary (Belgium/The Netherlands) from the freshwater tidal limits to the North Sea. Mar Chem 106:76-91
110. Vitousek PM, Reiners WA (1975) Ecosystem succession and nutrient retention: a hypothesis. Bioscience 25:370-381
111. von Sperber C, Kries H, Tamburini F, Bernasconi SM, Frossard E (2014) The effect of phosphomonoesterases on the oxygen isotope composition of phosphate. Geochim Cosmochim Acta 125:519-527
112. Walsh C (1979) Enzymatic reaction mechanisms. W H Freeman and Co, San Francisco
113. Wang Y, Huntington TG, Osher LJ, Wassenaar LI, Trumbore SE, Amundson RG, Harden JW, McKnight DM, Schiff SL, Aiken GR, Lyons WB, Aravena RO, Baron JS (1998) Carbon cycling in terrestrial environments. In: Kendall C, McDonnell JJ (eds) Isotope tracers in catchment hydrology. Elsevier Science, Amsterdam, pp 577-610
114. Weinhold F, Landis CR (2005) Valency and bonding: a natural bond orbital donor-acceptor perspective. Cambridge University Press, Cambridge
115. Wetzel RG (1983) Limnology. WB Sounders and Company, Philadelphia
116. Winogradsky S (1924) Sur la microflora autochtone de la terre arable. Comptes rendus hebdomadaires des seances de l'Academie des Sciences 178:1236-1239
117. Wolfenden R, Ridgway C, Young G (1998) Spontaneous hydrolysis of ionized phosphate monoesters and diesters and the proficiencies of phosphatases and phosphodiesterases as catalysts. J Am Chem Soc 120:833-834
118. Yang K, Metcalf WW (2004) A new activity for an old enzyme: Escherichia coli bacterial alkaline phosphatase is a phosphite-dependent hydrogenase. Proc Natl Acad Sci U S A 101:7919-7924
119. Young MB, McLaughlin K, Kendall C, Stringfellow W, Rollog M, Elsbury K, Donald E, Paytan A (2009) Characterizing the oxygen isotopic composition of phosphate sources to aquatic ecosystems. Environ Sci Technol 43:5190-5196
120. Zalatan JG, Fenn TD, Herschlag D (2008) Comparative enzymology in the alkaline phosphatase superfamily to determine the catalytic role of an active-site metal ion. J Mol Biol 384:1174-1189
121. Zohar I, Shaviv A, Klass T, Roberts K, Paytan A (2010) Method for the analysis of oxygen isotopic composition of soil phosphate fractions. Environ Sci Technol 44:7583-7588
122. Zyryanov AB, Vener AV, Salminen A, Goldman A, Lahti R, Baykov AA (2004) Rates of elementary catalytic steps for different metal forms of the family II pyrophosphatase from Streptococcus gordonii. Biochemistry 43:1065-1074