Two-dimensional arrangement of a functional protein by cysteine-gold interaction: enzyme activity and characterization of a protein monolayer on a gold substrate

Abstract

We have characterized the functional protein, myosin subfragment 1 (S1), attached to a gold substrate by the sulfhydryl groups of cysteine in proteins. The amino groups of the regulatory light chain (RLC) isolated from myosin were labeled with a radioisotope (125I), and the labeled RLC was incorporated into S1 from which the RLC had been removed. The radiation from 125I showed that S1 molecules had attached to the gold and, through the interference effect of the monochromatic radiation from 125I, provided information about the position of labeled RLC sites in the S1 monolayer. The interference fringes showed that the RLC was located close to the gold surface and that all of the adsorbed S1 molecules had the same orientation. We confirmed that the motor function of S1 on the gold surface is maintained by observing sliding movement at low ionic strength and by observing the detachment at high ionic strength of fluorescent actin filaments in the presence of ATP. We also found that the adsorbed S1 molecules were not removed from the Au surface by a reducing agent. Thus the Au-S bond is more stable than the S-S bond.

Gold is a T cell polyclonal activator in BN and LEW rats but favors IL-4 expression only in autoimmune prone BN rats

“…Four main conclusions may be drawn. [10]. Thus, it has been proposed that the benefi-cial effect of gold salts in rheumatoid arthritis patients may result from a loss of presentation of peptides containing Cys to autoreactive T cells [11] or from inhibition of signaling molecules [12] or of transcription factors [13].…”

Adlayer structures of dl-homocysteine and l-homocysteine thiolactone on Au(1 1 1) surface: an in situ STM study

“…Cysteine is a small and zwitterionic amino acid. Additionally, as a thiol molecule, the self-assembled monolayers of cysteine molecules on gold substrates by sulfur-gold bonds were used to immobilize proteins [4][5][6], which has been employed to fabricate artificial protein arrays and biosensors. So the molecular feature and adlayer structures of cysteine on gold surfaces have been investigated by scanning tunneling microscopy (STM), spectroscopic techniques and secondary ion mass spectrometry [7][8][9][10][11][12].…”

Differential interaction of silver nanoparticles with cysteine

“…It is a small, zwitterionic molecule, and well used in biochemical and electrochemical research. Understanding the characteristics of Cys on a solid surface is an important issue in protein study as well as in differentiating amino acid molecules [11][12][13]. Therefore, we have selected cysteine as a model biomolecule for interaction with plasmonic silver nanoparticles.…”