This paper presents a set of investigations on the binding of a metabolic inhibitor, azide with prosthetic heme group of biomolecules, hemin chloride (Hem) and cytochrome c (Cyt c) immobilized on Au and Ag nanoparticles. A variety of spectroscopic tools have been used to understand the chemistry occurring on the nanoparticle surface. While the nature of binding of the model system, hemin has been investigated by UV - visible, fluorescence, FTIR, and Raman spectroscopies, the azide binding has been studied in detail by MALDI-TOF MS. Hemin binding on the nanoparticle surface occurs through the carboxylic acid groups. The hemin - N3 adduct on the nanoparticle surface has been detected by mass spectrometry and its fragments have been studied by post source decay analysis. The chemistry of hemin on the nanoparticle surface has been compared with that of the protein, Cyt c. Azide binding of Cyt c requires thermal activation due to reduced accessibility of the heme center, unlike in the case of hemin. The binding chemistry is similar for free Cyt c and Cyt c bound to the nanoparticles. © 2005 American Chemical Society.

Pradeep Thalappil

Department Of Chemistry

Renjis T. Tom

Activation analysis

Enzyme inhibition

Fluorescence

Fourier transform infrared spectroscopy

Gold

Mass spectrometry

metabolism

Raman spectroscopy

Silver

Surface chemistry

Ultraviolet spectroscopy

Biomolecules

CYTOCHROME C (CYT C)

HEMIN

Thermal activation

Nanostructured materials

Azide

Cytochrome c

heme

nanoparticle

Azides

CYTOCHROME C GROUP

Cytochromes c

Nanoparticles

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Langmuir

In this paper, a summary of some of the recent research efforts in our laboratory on chemical interactions at noble metal nanoparticle surfaces is presented. The article is divided into five sections, detailing with (i) interactions of simple halocarbons with gold and silver nanoparticle surfaces at room temperature by a new chemistry and the exploitation of this chemistry in the extraction of pesticides from drinking water, (ii) interaction of biologically important proteins such as Cyt c, hemoglobin and myoglobin as well as a model system, hemin with gold and silver nanoparticles and nanorods forming nano-bio conjugates and their surface binding chemistry, (iii) formation of polymer-nano composites with tunable optical properties and temperature sensing characteristics by single and multi-step methodologies, (iv) nanomaterials-based flow sensors and (v) composites of noble metal nanoparticles and metallic carbon nanotubes showing visible fluorescence induced by metal-semiconductor transition. © 2009 by World Scientific Publishing Co. Pte. Ltd. All rights reserved.

Fulltext

Selected Topics in Nanoscience and Nanotechnology

Chemical interactions at noble metal nanoparticle surfaces - Catalysis, sensors and devices

Bioconjugates of the hemoproteins, myoglobin, and hemoglobin have been synthesized by their adsorption on spherical gold and silver nanoparticles and gold nanorods. The adsorption of hemoproteins on the nanoparticle surface was confirmed by their molecular ion signatures in matrix assisted laser desorption ionization mass spectrometry and specific Raman features of the prosthetic heme b units. High-resolution transmission electron microscopy (HRTEM) and UV-visible spectroscopy showed that the particles retain their morphology and show aggregation only in the case of silver. The binding of azide ion to the Fe(III) center of the prosthetic heme b moiety caused a red shift of the Soret band, both in the case of the bioconjugates and in free hemoproteins. This was further confirmed by the characteristic signature at 2050 cm-1 in the Fourier-transform infrared spectra, which corresponds to the asymmetric stretching of the Fe(III) bound azide. The retention of the chemical behavior of the prosthetic heme group after adsorption on the nanoparticle is interesting due to its implications in nanoparticle supported enzyme catalysis. The absence of morphology changes after the reaction of bioconjugates with azide ion observed in HRTEM studies implies the stability of nanoparticles under the reaction conditions. All these studies indicate the retention of protein structure after adsorption on the nanoparticle surface. © 2007 American Chemical Society.

Hemoprotein bioconjugates of gold and silver nanoparticles and gold nanorods: Structure-function correlations

Inorganic Chemistry

Control of Iron(III) Spin-State in the Model Complexes of Azide Hemoprotein by Porphycene, Corrphycene, and Hemiporphycene Macrocycles

The Journal of Physical Chemistry A

Spectroscopy of Hydrothermal Reactions. 24. Kinetics of Alkyl Azide Decomposition Channels and N3-Behavior in Water above 200 °C at 275 Bar

Unusual Spin State Equilibrium of Azide Metmyoglobin Induced by Ferric Corrphycene

Journal of the American Chemical Society

Selective examination of heme protein azide ligand-distal globin interactions by vibrational circular dichroism

Interaction of azide ion with hemin and cytochrome c immobilized on Au and Ag nanoparticles

Journal	Langmuir
ISSN	07437463
Open Access	No