Chall, Sayantani and Mati, Soumya Sundar and Das, Indranee and Kundu, Amrita and De, Goutam and Chattopadhyay, Krishnananda (2017) Understanding the Effect of Single Cysteine Mutations on Gold Nanoclusters as Studied by Spectroscopy and Density Functional Theory Modeling. Langmuir, 33 (43). pp. 12120-12129. ISSN 0743-7463

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Abstract

Fluorescent metal nanoclusters have generated considerable excitement in nanobiotechnology, particularly in the applications of biolabeling, targeted delivery, and biological sensing. The present work is an experimental and computational study that aims to understand the effects of protein environment on the synthesis and electronic properties of gold nanoclusters. MPT63, a drug target of Mycobacterium tuberculosis, was used as the template protein to synthesize, for the first time, gold nanoclusters at a low micromolar concentration of the protein. Two single cysteine mutants of MPT63, namely, MPT63G1y20Cys (mutant I) and MPT63Gly40Cys (mutant II) were employed for this study. The experimental results show that cysteine residues positioned in two different regions of the protein induce varying electronic states of the nanoclusters depending on the surrounding amino acids. A mixture of five-atom and eight -atom clusters was generated for each mutant, and the former was found to be predominant in both cases. Computational studies, including density functional theory (DFT), frontier molecular orbital (FMO), and natural bond orbital (NBO) calculations, validated the experimental observations. The as-prepared protein stabilized nanoclusters were found to have applications in the imaging of live cells.

Item Type:	Article
Subjects:	Engineering Materials
Divisions:	Nano-Structured Materials
Depositing User:	Bidhan Chaudhuri
Date Deposited:	23 Jan 2018 07:12
Last Modified:	23 Jan 2018 07:12
URI:	http://cgcri.csircentral.net/id/eprint/4002

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