Azurin immobilisation on thiol covered Au(111)

Abstract

Azurin is a blue single copper protein involved in the respiratory chain of denitrifying bacteria. The structural gene for azurin from Pseudomonas aeruginosa was cloned in an Escherichia coli recombinant strain. The protein overexpressed in the bacterial periplasmic space was subsequently purified. Two strategies were followed to anchor azurin to gold surfaces. First, the protein was immobilised on bare gold. Azurin adsorbs on gold via its disulfide group. Scanning tunnelling microscopy (STM) inspection of the azurin-Au(111) interface revealed the formation of a closely packed protein monolayer and allowed individual azurin molecules to be resolved. In order to uncouple the protein layer from the metal, the gold surfaces were then covered with self-assembled monolayers of 11-mercaptoundecanoic acid. The changes in the sample morphology due to the protein adsorption have been investigated by atomic force microscopy (AFM). A fairly uniform distribution of protein molecules covers the surface. Owing to the tip broadening effect, an average protein diameter of about 20 nm was measured. An upper limit of 1 nN for the non-disruptive imaging force in the contact mode was found

New Developments for the Site-Specific Attachment of Protein to Surfaces

“…Cavarelly et al 60 also used the naturally occurring and unique disulfide bond present in the protein azurin. This protein was able to form highly ordered films when reacted with gold.…”

Electrons and Hydrogen-Bond Connectivity in Liquid Water

“…For our basis set, neglecting the very small inter-molecular matrix elements was found to give an adequate approximation for the purposes of this paper. The strong excitonic effect introduced by the attraction between the core hole and the excited electron is estimated in the Z + 1 approximation [22].…”

“…We focus on two distinctive features of the XAS spectrum directly related to the pre-edge observed in the experiments: (i) the relative intensity of the peaks related to edge and pre-edge features, and (ii) the energy difference between both peaks ∆E. As discussed by Cavalleri et al [22], the spectral intensity is taken from the Z approximation (initial-state), while ∆E is obtained from the Z + 1 approximation, given its sensitivity to finalstate effects. Fig.…”

“…AIMD distributions reflect both the preference for the tetrahedral geometry and the flexibility given by the dynamical response of the electron cloud. It has been argued [13,22,38,39] that, in spite of these differences, AIMD lines up with any force field so far to produce qualitatively wrong configurational sampling of liquid water. It is certainly true that there are clear shortcomings in our scheme (BLYP approximations for exchange and correlation, neglect of protonic quantum effects) as well as in others.…”

Fabrication of functional biomolecular layer using recombinant technique for the bioelectronic device

“…And then the residual solution on Au surface was removed by N 2 gun. It is a very simple step compared with reported previously method using alkanethiol [22][23][24]. The schematic description of azurin immobilization is shown Fig.…”