Visit Incyte
Home | This Week's Contents  |  C&EN ClassifiedsSearch C&EN Online

Millennium Special Report
C&EN 75th Anniversary Issue
Related Stories
Related Site
Teikyo University
E-mail this article to a friend
Print this article
E-mail the editor
 Table of Contents
 C&EN Classifieds
 News of the Week
 Cover Story
 Editor's Page
 Government & Policy
  Government & Policy
 ACS News
 Digital Briefs
 ACS Comments
 Career & Employment
 Special Reports
 What's That Stuff?
 Pharmaceutical Century

 Hot Articles
 Safety  Letters

 Back Issues

 How to Subscribe
 Subscription Changes
 About C&EN
 Copyright Permission
 E-mail webmaster
April 23, 2001
Volume 79, Number 17
CENEAR 79 17 pp. 13
ISSN 0009-2347
[Previous Story] [Next Story]

ATP Synthase's Two-Step


By observing a gold bead attached to the rotor of the energy-converting enzyme ATP synthase, Japanese researchers have found that the rotor takes two steps per hydrolysis cycle [Nature, 410, 898 (2001)].

The results will help "solve the mechanism of this highly efficient, reversible motor," says Ryohei Yasuda, a physicist at Teikyo University Biotechnology Center. Previously, Yasuda and coworkers had shown that the rotor (orange in figure) moves in 120š steps, coinciding with sequential ATP hydrolysis on three of the enzyme's so-called b-subunits (blue). They observed that motion by attaching an actin filament to the rotor. However, the friction created by the filament blurred the picture.

"We refined the system by using a smaller marker," says Yasuda, who is now at Cold Spring Harbor Laboratory. With a 40-nm gold bead attached through streptavidin (red) linked to biotin, friction drops to one ten-thousandth of that caused by actin, allowing a resolution on the order of 0.1 millisecond.

The motion of the gold bead, observed through laser dark-field microscopy, reveals that the 120š step is composed of a 90š substep driven by ATP binding and a 30š substep due to product release. These steps likely correspond to different conformations already revealed by structural studies.

[Previous Story] [Next Story]


Chemical & Engineering News
Copyright © 2001 American Chemical Society

Visit Atofina
Home | Table of Contents | News of the Week | Cover Story
Business | Government & Policy | Science/Technology
Chemical & Engineering News
Copyright © 2001 American Chemical Society - All Right Reserved
1155 16th Street NW • Washington DC 20036 • (202) 872-4600 • (800) 227-5558

CASChemPortChemCenterPubs Page