Twisting of protein molecules in water is successfully captured on molecular movie

Apr 27, 2012
Fig. 1. Changes in the structure of the dimeric hemoglobin molecule. The relative positions of the two units gradually change, whereby the distance between the two units becomes shorter by 1.3 Ĺ and the units rotate 3.4 degrees relative to each other.

A research group led by Hyotcherl Ihee at the Korea Advanced Institute of Science and Technology (KAIST) observed twisting of protein molecules in an aqueous solution (which is very similar to the environment in vivo at room temperature) as an X-ray molecular movie with a precision of 100 picoseconds (one over one-ten-billionth of a second). They were assisted by Prof. Shin-ichi Adachi at the Institute of Materials Structure Science at the High Energy Accelerator Research Organization (KEK), Prof. Shin-ya Koshihara at the Graduate School of Science and Engineering at the Tokyo Institute of Technology, and a research group from the University of Chicago in the US.

Hemoglobin of clams consists of two weakly bonded units, each of which contains iron porphyrin (heme) complexes. Molecules of oxygen or reversibly bind to the iron and are thereby carried in the blood. The hemoglobin molecule was irradiated with laser light for a short period of time. The changes in the molecular structure of the protein that occurred after irradiation were tracked at the Photon Factory of KEK, using the time-resolved X-ray solution scattering method. In this study, laser light irradiation was used to break the bonds between the heme complexes in the and carbon monoxide to obtain a transient state in which carbon monoxide is dissociated from the protein. The structure of hemoglobin gradually changed within a timeframe from 100 ps (one-ten-billionth of a second ) to 10 ms (one-hundredth of a second), whereby the distance between the two units became shorter and the two units rotated by approximately 3 degrees relative to each other (Fig. 1).

This is a revolutionary method that can be used to visualize, as a molecular movie, various proteins moving naturally in environments very similar to the environments in vivo. Expectations are high that this new technology will able to analyze the molecular functions of proteins that are important in biological activities.

Explore further: Why plants don't get sunburn

add to favorites email to friend print save as pdf

Related Stories

Ringing the hemoglobin bell

Sep 08, 2011

(PhysOrg.com) -- Knowing the structure of a molecule is an important part of understanding it, but quite often it’s even more important to know how the molecule moves -- more specifically, the vibrational ...

Quick-Change Molecules Caught in the Act

Jun 01, 2010

(PhysOrg.com) -- The chemistry of life happens so fast that a millionth of a second is an eternity -- an eternity that is largely invisible to science. In that time, molecules change in ways we cannot see. ...

Unique E. coli protein may be not after all

Jan 03, 2012

A bacterial protein recently thought to be a unique mechanism for utilizing iron may not be after all. Researchers from the University of Georgia, the Fellowship for Interpretation of Genomes, the University of Oklahoma and ...

New Argonne study may shed light on protein-drug interactions

Jan 15, 2008

Proteins, the biological molecules involved in virtually every action of every organism, may themselves move in surprising ways, according to a recent study from the U.S. Department of Energy’s Argonne National Laboratory ...

Recommended for you

Why plants don't get sunburn

Oct 29, 2014

Plants rely on sunlight to make their food, but they also need protection from its harmful rays, just like humans do. Recently, scientists discovered a group of molecules in plants that shields them from ...

Viral switches share a shape

Oct 27, 2014

A hinge in the RNA genome of the virus that causes hepatitis C works like a switch that can be flipped to prevent it from replicating in infected cells. Scientists have discovered that this shape is shared by several other ...

'Sticky' ends start synthetic collagen growth

Oct 27, 2014

Rice University researchers have delivered a scientific one-two punch with a pair of papers that detail how synthetic collagen fibers self-assemble via their sticky ends.

Cell membranes self-assemble

Oct 27, 2014

A self-driven reaction can assemble phospholipid membranes like those that enclose cells, a team of chemists at the University of California, San Diego, reports in Angewandte Chemie.

Emergent behavior lets bubbles 'sense' environment

Oct 27, 2014

Tiny, soapy bubbles can reorganize their membranes to let material flow in and out in response to the surrounding environment, according to new work carried out in an international collaboration by biomedical ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.