AVS 53rd International Symposium
    Biomaterial Interfaces Friday Sessions
       Session BI-FrM

Paper BI-FrM11
Single Molecule Force Spectroscopy on 5'-Methyl thioadenosine/S-Adenosylhomocysteine Nucleosidase (MTAN) from Escherichia Coli by Atomic Force Microscopy

Friday, November 17, 2006, 11:20 am, Room 2014

Session: Biomolecular Surface Characterization II
Presenter: B.I. Kim, Boise State University
Authors: B.I. Kim, Boise State University
J.O. Holmes, Boise State University
K.A. Cornell, Boise State University
P. Deschatelets, Potentia Pharmaceuticals Inc.
Correspondent: Click to Email
5'-Methyl Thioadenosine/S-Adenosylhomocysteine Nucleosidase (MTAN) is a dual substrate specific enzyme that catabolizes 5'Methyl thioadenosine (MTA) or S-Adenosylhomocysteine (SAH) to form adenine and 5'-methylthioribose or S-ribosylhomocysteine, respectively, in many pathogenic microbes. MTAN is an ideal target for new antibiotic development because it has no corresponding human equivalent and recognizes a substrate that is not present in mammalian cells. Based on this interest, the binding mechanisms of various transition state analogues that inhibit the expression of MTAN were studied using the single molecule force-spectroscopy technique. Force-distance curves were measured as a function of separation distance between a probing molecule and the MTAN molecule under buffer conditions using atomic force microscopy (AFM). Various probing molecules were covalently linked via a flexible spacer polyethylene glycol (PEG) to the tip of an AFM. The force-distance curve exhibits an unbinding event in the retracting curve with a certain unbinding force. Single molecular binding strength, rate constant, and structural data for the binding pocket were extracted from several hundred force-distance curves and were analyzed statistically for each transition state analogue. The statistical values were compared with the equilibrium dissociation constants previously obtained by other groups. Single molecule force spectroscopy provides a new insight into the specific binding mechanism between the inhibitors and a MTAN molecule at the single molecular level.