Featured Research

from universities, journals, and other organizations

Measurements Of Protein Surface Verify Electrostatics Model

Date:
December 15, 1998
Source:
University Of Illinois At Urbana-Champaign
Summary:
Using a surface-force apparatus, researchers at the University of Illinois have measured the electrostatic properties of a protein surface at the molecular level. Their results provide the first direct comparison between localized measurements and theoretical predictions.

CHAMPAIGN, Ill. - Using a surface-force apparatus, researchers at the University of Illinois have measured the electrostatic properties of a protein surface at the molecular level. Their results provide the first direct comparison between localized measurements and theoretical predictions.

"We obtained direct measurements of the pH-dependent electrostatic charge density of a single binding face of the protein streptavidin," said Deborah Leckband, a U. of I. professor of chemical engineering. "Our measurements show excellent agreement with values predicted from theory, thus verifying the accuracy of our measurement technique."

Identifying the electrostatic properties of a protein surface is useful for interpreting biochemical data and for obtaining a better mechanistic understanding of the forces that govern a protein's behavior. Many researchers believe, for example, that complementary charge distributions can generate steering torques that act like tiny tractor beams that pull proteins into the right orientation for binding.

To probe the local surface charges, Leckband, biophysics professor Shankar Subramaniam and graduate research assistant Sanjeevi Sivasankar first prepared homogeneously oriented monolayers of streptavidin by anchoring the protein to a supported lipid bilayer.

Using a surface-force apparatus, they then measured directly the electrostatic surface potential of the protein monolayer at a variety of pH levels. They were thus able to isolate the point of zero charge for the binding face of the protein. Importantly, the measured value for the exposed protein surface differed from the point of zero charge for the net protein.

"The difference in the pH-dependence between the probed surface and the soluble protein clearly demonstrates that these force measurements indeed reflect the local charge density of the oriented protein, rather than its net charge," Leckband said.

The experimentally measured surface-charge densities were then compared with theoretical predictions of the electrostatic potential distribution around the protein surface.

"The calculated values agreed very closely with those obtained by the surface-force measurements," Leckband said. "This tells us not only that we can measure the local properties of protein surfaces at the molecular level, but also that current models are reasonably accurate."

While the study focused on the pH-dependence of electrostatic surface-charge densities, "this direct approach to probing the electrostatic features of proteins is applicable to investigations of any perturbation that alters the electrostatic composition of the surfaces of immobilized macromolecules," Leckband said.

The researchers announced their findings in the October issue of the Proceedings of the National Academy of Sciences.


Story Source:

The above story is based on materials provided by University Of Illinois At Urbana-Champaign. Note: Materials may be edited for content and length.


Cite This Page:

University Of Illinois At Urbana-Champaign. "Measurements Of Protein Surface Verify Electrostatics Model." ScienceDaily. ScienceDaily, 15 December 1998. <www.sciencedaily.com/releases/1998/12/981215081028.htm>.
University Of Illinois At Urbana-Champaign. (1998, December 15). Measurements Of Protein Surface Verify Electrostatics Model. ScienceDaily. Retrieved September 30, 2014 from www.sciencedaily.com/releases/1998/12/981215081028.htm
University Of Illinois At Urbana-Champaign. "Measurements Of Protein Surface Verify Electrostatics Model." ScienceDaily. www.sciencedaily.com/releases/1998/12/981215081028.htm (accessed September 30, 2014).

Share This



More Matter & Energy News

Tuesday, September 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Argentina's Tax Evaders Detected, Hunted Down by Drones

Argentina's Tax Evaders Detected, Hunted Down by Drones

AFP (Sep. 30, 2014) Argentina doesn't only have Lionel Messi the footballer, it has now also acquired "Mesi" the drone system which monitors undeclared mansions, swimming pools and soy fields to curb tax evasion in the country. Duration: 01:18 Video provided by AFP
Powered by NewsLook.com
Do Video Games Trump Brain Training For Cognitive Boosts?

Do Video Games Trump Brain Training For Cognitive Boosts?

Newsy (Sep. 29, 2014) More and more studies are showing positive benefits to playing video games, but the jury is still out on brain training programs. Video provided by Newsy
Powered by NewsLook.com
CERN Celebrates 60 Years of Science

CERN Celebrates 60 Years of Science

Reuters - Business Video Online (Sep. 29, 2014) CERN, the European Organisation for Nuclear Research, celebrates 60 years of bringing nations together through science. As Joanna Partridge reports from inside the famous science centre it's also planning to turn the Large Hadron Collider particle accelerator back on after an upgrade. Video provided by Reuters
Powered by NewsLook.com
This 'Invisibility Cloak' Is Simpler Than Most

This 'Invisibility Cloak' Is Simpler Than Most

Newsy (Sep. 28, 2014) Researchers from the University of Rochester have created a type of invisibility cloak with simple focal lenses. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins