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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Mechanistic Insights into Ultrasmall Gold Nanoparticle-Protein Interactions through Measurement of Binding Kinetics

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Ferreira, Rodrigo S. [1] ; Lira, Andre L. [1] ; Torquato, Ricardo J. S. [1] ; Schuck, Peter [2] ; Sousa, Alioscka A. [1]
Total Authors: 5
[1] Univ Fed Sao Paulo, Dept Biochem, BR-04044020 Sao Paulo, SP - Brazil
[2] Natl Inst Biomed Imaging & Bioengn, NIH, Bethesda, MD 20892 - USA
Total Affiliations: 2
Document type: Journal article
Source: Journal of Physical Chemistry C; v. 123, n. 46, p. 28450-28459, NOV 21 2019.
Web of Science Citations: 0

Gold nanoparticles (NPs) in the ultrasmall size regime provide a new paradigm in the way that nanomaterials can be used to regulate protein structure and function. However, the rational design of ultrasmall NPs as viable synthetic effectors of protein function requires detailed quantitative understanding of their biomolecular interactions. Herein, we focused on the kinetics of NP-protein complexation-an often neglected factor in studies at the bio-nanointerface-to gain molecular-level insights into mechanisms of interactions. The protein alpha-thrombin and ultrasmall gold NPs coated with p-mercaptobenzoic acid (AuMBA) and glutathione (AuGSH) were used as model systems in our studies. Binding kinetics was quantified by surface plasmon resonance (SPR) biosensing and stopped-flow spectroscopy. The results revealed strong and weak interactions of AuMBA and AuGSH toward thrombin (K-D similar to 30 nM and 20 mu M, respectively), as well as ``fast{''} and ``slow{''} association kinetics (k(on) similar to 10(6)-10(7) and 10(4) M-1 s(-1) respectively). The significantly smaller k(on) for AuGSH implied the presence of a larger energy barrier along the association pathway, presumably related to the penalty required to remove interfacial ions. Analysis of dissociation reactions revealed that thrombin interactions with both NPs formed transient, weakly adhesive complexes characterized by short residence times (t(r) = 1/k(off) similar to 0.1-16 s). Interestingly, the reverse reactions were best described by multiple dissociation processes suggesting a heterogeneous population of complexes stabilized to different extent. (AU)

FAPESP's process: 19/04372-6 - Interactions of ultrasmall gold nanoparticles with proteins and cells
Grantee:Alioscka Augusto Sousa
Support type: Regular Research Grants
FAPESP's process: 16/25535-2 - Biointeractions of gold nanoparticles: influence of macromolecular crowding and soft interactions
Grantee:Rodrigo da Silva Ferreira
Support type: Scholarships in Brazil - Post-Doctorate