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Abstract

We have used a prototype small cantilever atomic force microscope to observe, in real time, the interactions between individual protein molecules. In particular, we have observed individual molecules of the chaperonin protein GroES binding to and then dissociating from individual GroEL proteins, which were immobilized on a mica support. This work suggests that the small cantilever atomic force microscope is a useful tool for studying protein dynamics at the single molecule level.

High-speed atomic force microscopy coming of age

“…Details of the historical overviews of bio-AFM development and application are also given elsewhere [37,38]. 5 then the feedback scan is executed in the z-direction with frequency f = νV s to trace the sample surface.…”

Scaling Relations for Implantation of Size-Selected Au, Ag, and Si Clusters into Graphite

“…3(c) shows that, for higher energies (momenta), the Si data can be represented by a straight line with the same slope as the Au and Ag data. Thus, in the high energy regime, there is a universal behavior which unites the metal clusters, Au 7 and Ag 7 , with the semiconductor cluster, Si 7 . It appears that the same (viscous) retarding force, Eq.…”

“…However, when the cluster size is increased to n 7 the implantation depth can be defined to within only one atomic layer of the substrate; the mean diameter of Ag 7 clusters, 5:4 A [5], already exceeds the unit cell size in graphite, 2:42 A. Such a precise definition of the implantation depth for size-selected atomic clusters suggests the creation of novel nanoscale architectures, which may serve as model catalysts [6], prototypical binding sites to immobilize [7] biological molecules or nanoscale pores for DNA sequencing [8], or to create ''molecular corrals'' [9] by lateral etching.…”

“…The size-selected clusters in this study were produced by two methods: with an rf magnetron sputtering, gas aggregation cluster source [11,15] in the case of Ag 7 , Au 7 , and Si 7 clusters; and with a cesium sputtering source [16] for Ag 7 ÿ and Au 7 ÿ . The clusters were deposited in high vacuum ( 10 ÿ7 mbar) onto highly oriented pyrolytic graphite (HOPG) samples, cleaved shortly before introduction to the vacuum.…”

New directions in nanoscience: new challenges for surface analysis

“…6 Indeed, the molecules in question cover a huge range of size and complexity, from short-chain alkane thiols that may be assembled into an ordered monolayer on a gold surface in solution 7 to protein molecules obtained from living systems and containing thousands of atoms. 8 …”