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 July 28, 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 July 28, 2014).

Share This




More Matter & Energy News

Monday, July 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

The Carbon Trap: US Exports Global Warming

The Carbon Trap: US Exports Global Warming

AP (July 28, 2014) AP Investigation: As the Obama administration weans the country off dirty fuels, energy companies are ramping-up overseas coal exports at a heavy price. (July 28) Video provided by AP
Powered by NewsLook.com
Europe's Highest Train Turns 80 in French Pyrenees

Europe's Highest Train Turns 80 in French Pyrenees

AFP (July 25, 2014) Europe's highest train, the little train of Artouste in the French Pyrenees, celebrates its 80th birthday. Duration: 01:05 Video provided by AFP
Powered by NewsLook.com
TSA Administrator on Politics and Flight Bans

TSA Administrator on Politics and Flight Bans

AP (July 24, 2014) TSA administrator, John Pistole's took part in the Aspen Security Forum 2014, where he answered questions on lifting of the ban on flights into Israel's Tel Aviv airport and whether politics played a role in lifting the ban. (July 24) Video provided by AP
Powered by NewsLook.com
Creative Makeovers for Ugly Cellphone Towers

Creative Makeovers for Ugly Cellphone Towers

AP (July 24, 2014) Mobile phone companies and communities across the country are going to new lengths to disguise those unsightly cellphone towers. From a church bell tower to a flagpole, even a pencil, some towers are trying to make a point. (July 24) Video provided by AP
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:
from the past week

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