Complexation of U(VI) with highly phosphorylated protein, phosvitinA vibrational spectroscopic approach

Li, Bo; Raff, Johannes; Barkleit, Astrid; Bernhard, Gert; Foerstendorf, Harald

doi:10.1016/j.jinorgbio.2010.03.004

Cited by 51 publications

(55 citation statements)

References 46 publications

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“…Infrared modes of the phosphoryl group of phosphothreonine are expected to contribute in the 1300–750 cm −1 range [28], [43], [44]. Other IR contributions from the peptide may also be observed in this spectral region.…”

Section: Resultsmentioning

confidence: 99%

“…In fact, a tripodal derivative bearing gem -bis-phosphonate moieties was observed to demonstrate the highest complexation properties with uranyl in a screen of molecules developed for decorporation [25]. The affinity of uranyl for phosphate groups is also exemplified by the formation of uranyl-phosphate minerals such as meta-autunite, or by uranyl efficient binding to phospholipids [26], [27], and to phosphorylated proteins such as phosvitin [28] or the S-layer proteins of Bacillus sphaericus JG-A12 isolated from a uranium mining waste pile [4], [19]. However, there has been no quantitative analysis of the effect that adding a phosphoryl group has on uranyl affinity, in uranium binding sites of proteins.…”

Section: Introductionmentioning

confidence: 99%

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Modulating Uranium Binding Affinity in Engineered Calmodulin EF-Hand Peptides: Effect of Phosphorylation

et al. 2012

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To improve our understanding of uranium toxicity, the determinants of uranyl affinity in proteins must be better characterized. In this work, we analyzed the contribution of a phosphoryl group on uranium binding affinity in a protein binding site, using the site 1 EF-hand motif of calmodulin. The recombinant domain 1 of calmodulin from A. thaliana was engineered to impair metal binding at site 2 and was used as a structured template. Threonine at position 9 of the loop was phosphorylated in vitro, using the recombinant catalytic subunit of protein kinase CK2. Hence, the T9TKE12 sequence was substituted by the CK2 recognition sequence TAAE. A tyrosine was introduced at position 7, so that uranyl and calcium binding affinities could be determined by following tyrosine fluorescence. Phosphorylation was characterized by ESI-MS spectrometry, and the phosphorylated peptide was purified to homogeneity using ion-exchange chromatography. The binding constants for uranyl were determined by competition experiments with iminodiacetate. At pH 6, phosphorylation increased the affinity for uranyl by a factor of ∼5, from Kd = 25±6 nM to Kd = 5±1 nM. The phosphorylated peptide exhibited a much larger affinity at pH 7, with a dissociation constant in the subnanomolar range (Kd = 0.25±0.06 nM). FTIR analyses showed that the phosphothreonine side chain is partly protonated at pH 6, while it is fully deprotonated at pH 7. Moreover, formation of the uranyl-peptide complex at pH 7 resulted in significant frequency shifts of the νas(P-O) and νs(P-O) IR modes of phosphothreonine, supporting its direct interaction with uranyl. Accordingly, a bathochromic shift in νas(UO2)2+ vibration (from 923 cm−1 to 908 cm−1) was observed upon uranyl coordination to the phosphorylated peptide. Together, our data demonstrate that the phosphoryl group plays a determining role in uranyl binding affinity to proteins at physiological pH.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Modulating Uranium Binding Affinity in Engineered Calmodulin EF-Hand Peptides: Effect of Phosphorylation

et al. 2012

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“…However, in addition to the specific bindings, proteins employ various functional groups that have potentially associated with metals. The literature report as high as 83–465 mole cadmium per mole biopolymer [24, 25]. The results of UF method shown in Figure 2 include both specific and nonspecific bindings.…”

Section: Resultsmentioning

confidence: 99%

Measurement of Cadmium Ion in the Presence of Metal‐Binding Biopolymers in Aqueous Sample

Fukushi

2013

The Scientific World Journal

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In aqueous environment, water-soluble polymers are effectively used to separate free metal ions from metal-polymer complexes. The feasibilities of four different analytical techniques, cadmium ion-selective electrode, dialysis sack, chelate disk cartridge, and ultrafiltration, in distinguishing biopolymer-bound and nonbound cadmium in aqueous samples were investigated. And two different biopolymers were used, including bovine serum albumin (BSA) and biopolymer solution extracted from cultivated activated sludge (ASBP). The ISE method requires relatively large amount of sample and contaminates sample during the pretreatment. After the long reaction time of dialysis, the equilibrium of cadmium in the dialysis sack would be shifted. Due to the sample nature, chelate disk cartridge could not filter within recommended time, which makes it unavailable for biopolymer use. Ultrafiltration method would not experience the difficulties mentioned above. Ultrafiltration method measuring both weakly and strongly bound cadmium was included in nominally biopolymer-cadmium complex. It had significant correlation with the Ion-selective electrode (ISE) method (R 2 = 0.989 for BSA, 0.985 for ASBP).

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“…The most common isotope of natural uranium is 238 U, having a negligible radiotoxicity due to its geologically long half-life (4.5 × 10 9 a). However, because of its superior binding affinity toward biomolecules [2], ingestion and inhalation of uranium could cause certain acute and/or chronic harmful effects, especially the kidney damage from acute internal exposure to uranium and its compounds [2,3]. Thus it actually is a highly biotoxic radionuclide while is being introduced into the fragile ecosystem through a combination of natural processes as well as anthropogenic activities [4].…”

Section: Introductionmentioning

confidence: 99%

Selective solid-phase extraction of uranium by salicylideneimine-functionalized hydrothermal carbon

Wang

Cao

et al. 2012

Journal of Hazardous Materials

150

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Complexation of U(VI) with highly phosphorylated protein, phosvitinA vibrational spectroscopic approach

Cited by 51 publications

References 46 publications

Modulating Uranium Binding Affinity in Engineered Calmodulin EF-Hand Peptides: Effect of Phosphorylation

Modulating Uranium Binding Affinity in Engineered Calmodulin EF-Hand Peptides: Effect of Phosphorylation

Measurement of Cadmium Ion in the Presence of Metal‐Binding Biopolymers in Aqueous Sample

Selective solid-phase extraction of uranium by salicylideneimine-functionalized hydrothermal carbon

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