Interaction of metal nanoparticles with recombinant arginine kinase from Trypanosoma brucei:Thermodynamic and spectrofluorimetric evaluation

Adeyemi, O. S. and Whiteley, C.G. (2014) Interaction of metal nanoparticles with recombinant arginine kinase from Trypanosoma brucei:Thermodynamic and spectrofluorimetric evaluation. Biochimica et Biophysica Acta.

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Abstract

Background: Trypanosoma brucei, responsible for African sleeping sickness, is a lethal parasite against which thereis need for new drug protocols. It is therefore relevant to attack possible biomedical targets with specific prepa-rations and since arginine kinase does not occur in humans but is present in the parasite it becomes a suitabletarget.Methods:Fluorescence quenching, thermodynamic analysis and FRET have shown that arginine kinase fromT.bruceiinteracted with silver or gold nanoparticles.Results:The enzyme only had one binding site. At 25 °C the dissociation (Kd)andStern–Volmer constants(KSV) were 15.2 nM, 0.058 nM−1[Ag]; and 43.5 nM, 0.052 nM−1[Au] and these decreased to 11.2 nM,0.041 nM−1[Ag]; and 24.2 nM, 0.039 nM−1[Au] at 30 °C illustrating static quenching and the formationof a non-fluorescentfluorophore–nanoparticle complex. Silver nanoparticles bound to arginine kinasewith greater affinity, enhancedfluorescence quenching and easier access to tryptophan molecules thangold. NegativeΔHandΔG values implied that the interaction of both Ag and Au nanoparticles with argininekinase was spontaneous with electrostatic forces. FRET confirmed that the nanoparticles were bound2.11 nm [Ag] and 2.26 nm [Au] from a single surface tryptophan residue.Conclusions:The nanoparticles bind close to the arginine substrate through a cysteine residue that controlsthe electrophilic and nucleophilic characters of the substrate arginine–guanidinium group crucial for enzy-matic phosphoryl transfer between ADP and ATP.General significance:The nanoparticles of silver and gold interact with arginine kinase fromT.bruceiandmay prove to have far reaching consequences in clinical trials.

Item Type:	Article
Subjects:	Q Science > QH Natural history > QH426 Genetics
Depositing User:	Mr DIGITAL CONTENT CREATOR LMU
Date Deposited:	16 Sep 2019 11:03
Last Modified:	16 Sep 2019 11:03
URI:	https://eprints.lmu.edu.ng/id/eprint/2224

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