Single-molecule force spectroscopy approach to enzyme catalysis
Journal of Biological Chemistry
Enzymatic catalysis has been traditionally studied using a diverse set of techniques such as bulk biochemistry, X-ray crystallography and NMR. Recently, single-molecule force spectroscopy by atomic force microscopy has been used as a new tool to study the catalytic properties of an enzyme. In this approach, a mechanical force ranging up to hundreds of pico Newtons is applied to the substrate of an enzymatic reaction, altering the conformational energy of the substrate-enzyme interactions during catalysis. From these measurements the force dependency of an enzymatic reaction can be determined. The force dependency provides valuable new information about the dynamics of enzymatic catalysis with sub-Ångström resolution, a feat unmatched by any other current technique. To date, single-molecule force spectroscopy has been applied to gain insight into the reduction of disulfide bonds by different enzymes of the thioredoxin family. This review aims to present a perspective on this new approach to study enzyme catalysis and summarize the results that have already been obtained from it. Finally, the specific requirements which must be fulfilled in order to apply this new methodology to any other enzyme will be discussed.