Scanning Tunneling Microscopy Imaging of Biomolecules: I. Tubulin in Microtubules and Monolayers II. Bacterial Luciferase—A Model System for Anesthesia

We used scanning tunneling microscopy (STM) to image two types of biomolecules using both graphite and gold substrates: 1) tubulin — the component protein of cytoskeletal microtubules — in two different forms: cylindrical microtubules and in zinc-induced tubulin monolayer sheets. In both cases STM images show periodic structures whose dimensions correlate with tubulin monomers and dimers. The shapes of the dimers differ in the two cases, apparently because of different surface charge distributions. 2) bacterial luciferase, a photoemitting enzyme whose function is inhibited by general anesthetic gases proportional to their anesthetic potency. We imaged bacterial luciferase in its “activated” form (in the presence of NADH) and in ethanol, which acts as an anesthetic.