A Carbon-Phosphorus Bond in Nature

Kittredge, James S.; Roberts, Eugene

doi:10.1126/science.164.3875.37

Cited by 197 publications

(75 citation statements)

References 63 publications

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“…44 and references therein). Lipid material and cell membranes are the major reservoir of phosphonates, but they also occur in proteins (45) and polysaccharides (46), but little is known about why they are produced (47,48).…”

Section: Biotic Evidencementioning

confidence: 99%

Rethinking early Earth phosphorus geochemistry

Pasek

2008

Proc. Natl. Acad. Sci. U.S.A.

236

209

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Phosphorus is a key biologic element, and a prebiotic pathway leading to its incorporation into biomolecules has been difficult to ascertain. Most potentially prebiotic phosphorylation reactions have relied on orthophosphate as the source of phosphorus. It is suggested here that the geochemistry of phosphorus on the early Earth was instead controlled by reduced oxidation state phosphorus compounds such as phosphite (HPO 3 2؊ ), which are more soluble and reactive than orthophosphates. This reduced oxidation state phosphorus originated from extraterrestrial material that fell during the heavy bombardment period or was produced during impacts, and persisted in the mildly reducing atmosphere. This alternate view of early Earth phosphorus geochemistry provides an unexplored route to the formation of pertinent prebiotic phosphorus compounds, suggests a facile reaction pathway to condensed phosphates, and is consistent with the biochemical usage of reduced oxidation state phosphorus compounds in life today. Possible studies are suggested that may detect reduced oxidation state phosphorus compounds in ancient Archean rocks.meteorites ͉ origins of life ͉ phosphonates ͉ prebiotic ͉ redox chemistry P hosphorus (P) is a key biologic element and is the limiting reagent in many ecosystems. Phosphorus is ubiquitous in biochemistry because phosphorylated biomolecules play major roles in replication and information (as RNA and DNA), metabolism (as ATP, NADPH, and other coenzymes), and structure (as phospholipids). Several key properties of P as phosphate make it advantageous to biologic systems, including thermodynamic instability coupled with kinetic stability, charge and coordination state, and a constant oxidation state under typical redox conditions (1). These features are especially critical to the formation of large informational polymers, and hence highly relevant to the origin and development of early life. Phosphorus Geochemistry and CosmochemistryThe major forms of P in life are summarized in Fig. 1. Inorganic P compounds used by life include orthophosphate, pyrophosphate and other condensed phosphates, phosphite, hypophosphite, and phosphine. These inorganic forms are either used by organisms as sources of P for the synthesis of organic-P biomolecules or are possible metabolic by-products of P metabolism (PH 3 ). Additionally, orthophosphate acts as a buffer in many cells, keeping pH constant at Ϸ7. Organic forms of P include compounds with C-O-P linkages and compounds with C-P linkages, and both are formed from inorganic P by using enzymes.Phosphorus is a lithophile element at the redox conditions on the surface of the Earth, and hence orthophosphate is the dominant form of inorganic P on the surface of the Earth today. The concentration of orthophosphate is water-buffered by the solubility of orthophosphate minerals like apatite, Ca 5 (PO 4 ) 3 (OH,F,Cl), on the present-day Earth, and of whitlockite, Ca 9 MgH(PO 4 ) 7 , and brushite, CaHPO 4 ⅐2H 2 O, before the rise of life-mediated apatite deposition (2). Because ...

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Section: Biotic Evidencementioning

confidence: 99%

Rethinking early Earth phosphorus geochemistry

Pasek

2008

Proc. Natl. Acad. Sci. U.S.A.

236

209

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“…Phosphonates have been identified in bacteria, ciliates, and higher organisms (Alhadeff & Daves Jr., 1970), as well as in marine sediments . Preferential preservation of these compounds has been hypothesized based on their stability to acid hydrolysis (Aalbers & Bieber, 1968;Kittredge & Roberts, 1969) and resistance to phosphatases (Rosenberg & La Nauze, 1967;Rosenthal & Pousada, 1968;Rosenthal & Ham, 1970). An increase in the relative importance of these compounds with depth in sediments would indicate that chemical structure is an important control on the rate of organic P degradation in these sediments.…”

Section: Mineral Surface Areamentioning

confidence: 99%

Organic phosphorus in marine sediments : chemical structure, diagenetic alteration, and mechanisms of preservation

Laarkamp¹

2000

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Phosphorus, an essential nutrient, is removed from the oceans only through burial with marine sediments. Organic phosphorus (Po,g) constitutes an important fraction (ca. 25%) oftotal-P in marine sediments. However, given the inherent lability of primary Po,g biochemicals, it is a puzzle that any Pm, is preserved in marine sediments. The goal of this thesis was to address this apparent paradox by linking bulk and molecular-level Po" information.A newly-developed sequential extraction method, which isolates sedimentary Po" reservoirs based on solubility, was used in concert with 3lp nuclear magnetic resonance spectroscopy (31p_NMR) to quantify Po,g functional group concentrations. The coupled extraction/ 31 P-NMR method was applied to three sediment cores from the Santa Barbara Basin, and the first-ever high-resolution depth profiles of molecular-level Po,g distribution during diagenesis were generated.These depth profiles were used to consider regulation of Pm, distribution by biomass abundance, chemical structure, and physical protection mechanisms. Biomass cannot account for more than a few percent of sedimentary Po,g. No evidence for direct structural control on remineralization of Po,g was found. Instead, sorptive protection appears to be an important mechanism for Po,g preservation, and structure may act as a secondary control due to preferential sorption of specific Pm, compound classes.

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“…While admitting that PH3 production as part of a pH-stat mechanism is rather unlikely in view of the toxicity of PH3 (at least to animals: Toy, 1973) and its autoignitability, there is a possibility that partial reduction of orthophosphate can occur in living organisms. This is witnessed by the occurrence of aminoethylphosphonic acid in the membrane lipid (phosphonolipid) and protein (phosphonoprotein) fractions of many organisms, including photolithotrophs (Thompson, Morris & Smith, 1969;Kittredge & Roberts, 1969;Antia, 1979). While it is possible to construe the synthesis of aminoethylphosphonic acid [H3N"''CH2CH2PO(OH)O"] as occurring by a reductive mechanism, with ethanolamine (H3N"'"CH2CH2OH) and orthophosphate as the substrates, it seems likely that the C-P bond is formed by a rearrangement of phosphoenolpyruvate to form 3-phosphonopyruvate, with subsequent amination and decarboxylation (Kitteredge & Roberts, 1969).…”

Section: Phosphorusmentioning

confidence: 99%

BIOCHEMICAL DISPOSAL OF EXCESS H⁺IN GROWING PLANTS?

Raven

1986

New Phytologist

141

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SUMMARY Many data support the view that, when NH4+ [or N2, NH3, or CO(NH2)2] is the N source for plant cell growth, the excess H+ generated in the synthesis of core metabolites is excreted to the bathing medium (biophysical pH‐stat). This paper explores the possibility that a ‘biochemical’ disposal of these excess H+ could occur, thus allowing net NHJ assimilation to take place in the shoot of land plants. A‘biochemical’ H+‐neutralizing pH‐stat requires that a non‐toxic resource be taken into the plant in a form in which metabolism can convert into a non‐toxic product with H+ consumption or OH− production. This possibility was explored for reductive metabolism of B(OH)3, Si (OH)4, H2PO4−, H2AsO4−, O2, SO42, SeO42− and HVO42; and for oxidative metabolism of Cr, Br−, I−, Fe2+ and Mn2+. For B(OH)3 and Si(OH)4, reductive metabolism (even if it were thermo‐dynamically possible, granted the reductants available to plants) does not involve significant 11+ removal. H2PO4− reduction may be thermodynamically possible, but is quantitatively insignificant as an H+ sink in plants. H2AsO4− reduction is probably a detoxification mechanism, and it is not a significant H+ sink in plants for which quantitative data are available. O2 assimilation (reduction) into ‐OH, and thence ≡O+, occurs in anthocyanin synthesis, but not to an extent which disposes of much of the excess H+ produced in growth with NHJ as N source. SO42− reduction in excess of that required by primary, core metabolism (i.e. that leading to amino acids, thylakoid sulpholipid and cell wall esters) can generate OH−, but such ‘secondary’ SO42− metabolism is related to osmoregulation and to chemical defence rather than to H+ disposal per se. The quantity of S metabolism which is ‘negotiable’ is not, apparently, adequate to neutralize a substantial fraction of excess H+ formed during growth. SeO4−2 reduction and assimilation performs largely a detoxification and/or chemical defence role, and the quantities involved (even in Se‐accumulators) do not generate enough OH− to offset much of the excess H+ formed during growth. Vanadate reduction is quantitatively insignificant as an H+ sink. Oxidation of Cl−, Br− and I− in incorporation into C‐halide groups is, in land plants, a quantitatively insignificant process. H+ disposal via HCl volatalization from an aqueous phase of low pH which contains Cl− does not seem to be an important sink for H+ in terrestrial plants. Oxidation of F− to form ≡C‐F usually produces CH2F.COO− with no net H+ consumption. Oxidation of Fe2+ and Mn2+ is H+‐consuming as long as oxides or hydroxides of Fe3 and Mn4+ are not formed. However, the oxides and hydroxides are often formed so that the oxidation processes consume OH− rather than H+. These quantitative considerations, together with those of the availability of starting materials and the toxicity of end products suggest that the H+‐consuming processes, even in combination, probably cannot dispose of all of the H+ generated in growth with NHJ as N source. In general, these H+‐consuming reactions se...

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A Carbon-Phosphorus Bond in Nature

Cited by 197 publications

References 63 publications

Rethinking early Earth phosphorus geochemistry

Rethinking early Earth phosphorus geochemistry

Organic phosphorus in marine sediments : chemical structure, diagenetic alteration, and mechanisms of preservation

BIOCHEMICAL DISPOSAL OF EXCESS H⁺IN GROWING PLANTS?

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A Carbon-Phosphorus Bond in Nature

Cited by 197 publications

References 63 publications

Rethinking early Earth phosphorus geochemistry

Rethinking early Earth phosphorus geochemistry

Organic phosphorus in marine sediments : chemical structure, diagenetic alteration, and mechanisms of preservation

BIOCHEMICAL DISPOSAL OF EXCESS H+IN GROWING PLANTS?

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BIOCHEMICAL DISPOSAL OF EXCESS H⁺IN GROWING PLANTS?