The use of polyoxometalates in protein crystallography – An attempt to widen a well-known bottleneck

Bijelic, Aleksandar; Rompel, Annette

doi:10.1016/j.ccr.2015.03.018

Cited by 226 publications

(196 citation statements)

References 113 publications

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“…The structure of the latent AUS1 form was obtained by automated model building using AUTOBUILD from the PHENIX suite, after placing the refined catalytically active main core with PHASER (MR) in the asymmetric unit. Restraints for the polyoxometalate hexatungstotellurate (VI), used as a cocrystallization agent for recombinantly expressed AUS1 (24,50), were obtained with phenix.reel and phenix.elbow as previously reported (27, 51, 52) using the crystal structure of hexatungstotellurate (VI) (53). The quality of the models was validated by MOLPROBITY (54).…”

Section: Methodsmentioning

confidence: 99%

Aurone synthase is a catechol oxidase with hydroxylase activity and provides insights into the mechanism of plant polyphenol oxidases

Molitor

Mauracher

Rompel

2016

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

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121

109

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Tyrosinases and catechol oxidases belong to the family of polyphenol oxidases (PPOs). Tyrosinases catalyze the o-hydroxylation and oxidation of phenolic compounds, whereas catechol oxidases were so far defined to lack the hydroxylation activity and catalyze solely the oxidation of o-diphenolic compounds. Aurone synthase from Coreopsis grandiflora (AUS1) is a specialized plant PPO involved in the anabolic pathway of aurones. We present, to our knowledge, the first crystal structures of a latent plant PPO, its mature active and inactive form, caused by a sulfation of a copper binding histidine. Analysis of the latent proenzyme's interface between the shielding C-terminal domain and the main core provides insights into its activation mechanisms. As AUS1 did not accept common tyrosinase substrates (tyrosine and tyramine), the enzyme is classified as a catechol oxidase. However, AUS1 showed hydroxylase activity toward its natural substrate (isoliquiritigenin), revealing that the hydroxylase activity is not correlated with the acceptance of common tyrosinase substrates. Therefore, we propose that the hydroxylase reaction is a general functionality of PPOs. Molecular dynamics simulations of docked substrate-enzyme complexes were performed, and a key residue was identified that influences the plant PPO's acceptance or rejection of tyramine. Based on the evidenced hydroxylase activity and the interactions of specific residues with the substrates during the molecular dynamics simulations, a novel catalytic reaction mechanism for plant PPOs is proposed. The presented results strongly suggest that the physiological role of plant catechol oxidases were previously underestimated, as they might hydroxylate their-so far unknown-natural substrates in vivo.crystal structure | tyrosinase | catechol oxidase | type III copper protein | mechanism

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Section: Methodsmentioning

confidence: 99%

Aurone synthase is a catechol oxidase with hydroxylase activity and provides insights into the mechanism of plant polyphenol oxidases

Molitor

Mauracher

Rompel

2016

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

Self Cite

121

109

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“…4,9,10,19 Recently, decavanadate has also found application in other processes such as aerobic oxidation of starch, solar-driven photocatalysis and protein crystallography. [20][21][22] Depending on factors such as vanadate concentration, pH and ionic strength, different vanadate oligomeric species can occur simultaneously in vanadium(V) solutions, including monomeric (V 1 4,23,24 These ortho and metavanadate species are comprised of tetrahedral vanadate units. In addition to them, the decavanadate ion, V 10 , which consists of octahedral vanadate units, also occurs in solution.…”

Section: Introductionmentioning

confidence: 99%

Characterization of decavanadate and decaniobate solutions by Raman spectroscopy

et al. 2016

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The decaniobate ion, (Nb 10 = [Nb 10 O 28 ] 6− ) being isoelectronic and isostructural with the decavanadate ion (V 10 = [V 10 O 28 ] 6− ), but chemically and electrochemically more inert, has been useful in advancing the understanding of V 10 toxicology and pharmacological activities. In the present study, the solution chemistry of Nb 10 and V 10 between pH 4 and 12 is studied by Raman spectroscopy. The Raman spectra of V 10show that this vanadate species dominates up to pH 6.45 whereas it remains detectable until pH 8.59, which is an important range for biochemistry. Similarly, Nb 10 is present between pH 5.49 and 9.90 and this species remains detectable in solution up to pH 10.80. V 10 dissociates at most pH values into smaller tetrahedral vanadate oligomers such as V 1 and V 2 , whereas Nb 10 dissociates into Nb 6 under mildly (10 > pH > 7.6) or highly alkaline conditions. Solutions of V 10 and Nb 10 are both kinetically stable under basic pH conditions for at least two weeks and at moderate temperature. The Raman method provides a means of establishing speciation in the difficult niobate system and these findings have important consequences for toxicology activities and pharmacological applications of vanadate and niobate polyoxometalates.

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“…Polyoxometalates (POMs) are discrete metal oxide clusters that are of current interest as soluble metal oxides, as well as for their application in catalysis, medicine, and materials science [1][2][3][4][5][6][7][8][9][10][11][12][13]. Recently, open-Wells-Dawson POMs have been reported as an emerging class of POMs [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28].…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Structure, and Characterization of In10-Containing Open-Wells–Dawson Polyoxometalate

et al. 2016

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The use of polyoxometalates in protein crystallography – An attempt to widen a well-known bottleneck

Abstract: Graphical abstract

Cited by 226 publications

References 113 publications

Aurone synthase is a catechol oxidase with hydroxylase activity and provides insights into the mechanism of plant polyphenol oxidases

Aurone synthase is a catechol oxidase with hydroxylase activity and provides insights into the mechanism of plant polyphenol oxidases

Characterization of decavanadate and decaniobate solutions by Raman spectroscopy

Synthesis, Structure, and Characterization of In10-Containing Open-Wells–Dawson Polyoxometalate

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