Fifteenth Sigma Xi Postdoctoral Poster Abstract

SELF-ASSEMBLY OF PLANT LECTINS ON GOLD SURFACES

Todd A. Morris*, Alexander W. Peterson*, Illarion V. Turko^†, and Michael J. Tarlov*

The immobilization of lectins on suitable substrates is a crucial step in the development of glycoprotein and cell surface carbohydrate assays. Most protein therapeutics made by the biotechnology industry are glycoproteins and lectin arrays are a promising technology for rapid glycoprofiling of these products for process monitoring and quality control applications.  Carbohydrates also decorate cell surfaces and play an important role in cellular communication, adhesion, development, and cancerous cell growth. An appropriate lectin-based matrix array could be employed to screen for malignant cells.  In most procedures, the fabrication of a lectin-based array requires that the substrate surface first must be modified with an organic film to anchor the immobilized lectin in its native, biologically-active state.  A variety of surface chemistries have been developed to accomplish this goal.  In contrast, our approach has been to modify the protein with a thiol (-SH) functionality to facilitate self-assembly of the lectin onto bare gold surfaces. The plant lectins used were Concanavalin A (ConA), peanut agglutinin (PNA), and wheat germ agglutinin (WGA). A facile reaction between 2-iminothiolane and e-NH₂ groups of the lectin’s lysine residues generated the intended thiol functionality.   The degree of thiolation was determined by UV-Vis spectroscopy and MALDI-TOF mass spectrometry. Exposure of bare gold surfaces to an aqueous solution of the modified protein results in spontaneous formation of lectin films that were characterized by reflection-absorption infrared spectroscopy (RAIRS) and x-ray photoelectron spectroscopy (XPS). Surface plasmon resonance spectroscopy (SPR) allowed in situ monitoring of lectin film formation. The retained biological activity of the lectin films was demonstrated with lectin-specific carbohydrate solutions.

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*National Institute of Standards and Technology, Gaithersburg , MD 20899

^†Center for Advanced Research in Biotechnology, Rockville, MD 20850

Author Information

Author: Todd Morris

Mentor: Michael Tarlov

Division: Process Measurements Division, 836

Laboratory: Chemical Science and Technology Laboratory

Room: B328

Building: Physics Building (221)

Mail Stop: 8362

Telephone: (301) 975-2563

Fax: (301) 975-2643

e-mail: todd.morris@nist.gov

Sigma Xi membership: no

Category: Chemistry