Skip to main content
  • Home
  • About
  • Faculty Experts
  • For The Media
  • ’Cuse Conversations Podcast
  • Topics
    • Alumni
    • Events
    • Faculty
    • Students
    • All Topics
  • Contact
  • Submit
STEM
  • All News
  • Arts & Culture
  • Business & Economy
  • Campus & Community
  • Health & Society
  • Media, Law & Policy
  • STEM
  • Veterans
  • University Statements
  • Syracuse University Impact
  • |
  • The Peel
  • Athletics
Sections
  • All News
  • Arts & Culture
  • Business & Economy
  • Campus & Community
  • Health & Society
  • Media, Law & Policy
  • STEM
  • Veterans
  • University Statements
  • Syracuse University Impact
  • |
  • The Peel
  • Athletics
  • Home
  • About
  • Faculty Experts
  • For The Media
  • ’Cuse Conversations Podcast
  • Topics
    • Alumni
    • Events
    • Faculty
    • Students
    • All Topics
  • Contact
  • Submit
STEM

Discovery by SU physicist alters conventional understanding of sight

Friday, June 24, 2011, By News Staff
Share
College of Arts and SciencesResearch and Creative

A discovery by a team of researchers led by a Syracuse University physicist sheds new light on how the vision process is initiated. For almost 50 years, scientists have believed that light signals could not be initiated unless special light-receptor molecules in the retinal cells first changed their shape in a process called isomerization. However, the SU research team, which includes researchers from Columbia University, has demonstrated that visual signals can be initiated in the absence of isomerization.

foster“We have demonstrated that chromophores (light-absorbing substances in retinal photoreceptor molecules), do not have to change shape in order to trigger the visual signal,” says Kenneth Foster, professor of physics in The College of Arts and Sciences. “The shape-change that results from isomerization is actually the second step in the process. Historically, scientists have focused on isomerization without realizing there is an earlier and more crucial first step.”

The research was published online June 23 in the journal Chemistry and Biology and is the cover article for the print version to appear June 24. The work was done in collaboration with Juree Saranak, research assistant professor in the Department of Physics; and Koji Nakanishi, professor of chemistry at Columbia University. Nakanishi’s group was responsible for the synthetic chemistry that went into the compounds tested at SU. The National Institutes of Health funded the research.

Chromophores absorb light after it enters the eye, setting off an extremely rapid series of complex molecular changes that enable light signals to be transmitted to, and interpreted by, the brain so that we can visually perceive the world around us. Visual chromophores are composed of retinal (a type of vitamin A), which attaches to a protein (opsin) to form rhodopsin.

Foster’s team of researchers discovered that the visual process is initiated by the redistribution of electrons on the chromophores, which occurs during the first few femtoseconds (one-quadrillionth of a second) after light enters the eye. Their experiments showed that when a chromophore absorbs a photon of light, electrons move from the chromophore’s “free” end to the place where it attaches to opsin. The movement of the electrons causes a change in the electrical field surrounding the chromophore. That change is detected by nearby amino acids that are highly sensitive to changes in the electrical field. These amino acids, in turn, signal the rest of the rhodopsin molecule to initiate the visual process.

“We found that the complete blocking of isomerization of the chromophore does not preclude vision in our model organism,” Foster says. “The signal is triggered as a result of an electronic coupling instead of a geometric change in the chromophore’s structure, as previously hypothesized. We believe this is a universal mechanism that activates all rhodopsins present in organisms from bacteria to mammals.”

Foster attributes his findings to new technologies and scientific information not available 50 years ago, when scientists first tried to understand how people see. “Fifty years ago, scientists had little knowledge of the structure of rhodopsins,” he says. “Advances in technology have enabled scientists to determine the rhodopsin structure at the level of the amino acids, which enables us to design sensitive experiments to test our hypotheses.”

  • Author

News Staff

  • Recent
  • Calling All Alumni Entrepreneurs: Apply for ’CUSE50 Awards
    Tuesday, June 24, 2025, By John Boccacino
  • Swinging Into Summer: Syracuse International Jazz Fest Returns With Star Power, Student Talent and a Soulful Campus Finale
    Tuesday, June 24, 2025, By Kathleen Haley
  • Iran Escalation: Experts Available This Week
    Tuesday, June 24, 2025, By Vanessa Marquette
  • Retiring University Professor and Decorated Public Servant Sean O’Keefe G’78 Reflects on a Legacy of Service
    Tuesday, June 24, 2025, By John Boccacino
  • SCOTUS Win for Combat Veterans Backed by Syracuse Law Clinic
    Monday, June 23, 2025, By Vanessa Marquette

More In STEM

WiSE Hosts the 2025 Norma Slepecky Memorial Lecture and Undergraduate Research Prize Award Ceremony

This spring, Women in Science and Engineering (WiSE) held its annual Norma Slepecky Memorial Lecture and Award Ceremony. WiSE was honored to host distinguished guest speaker Joan-Emma Shea, who presented “Self-Assembly of the Tau Protein: Computational Insights Into Neurodegeneration.” Shea…

Endowed Professorship Recognizes Impact of a Professor, Mentor and Advisor

Bao-Ding “Bob” Cheng’s journey to Syracuse University in pursuit of graduate education in the 1960s was long and arduous. He didn’t have the means for air travel, so he voyaged more than 5,000 nautical miles by boat from his home…

Forecasting the Future With Fossils

One of the most critical issues facing the scientific world, no less the future of humanity, is climate change. Unlocking information to help understand and mitigate the impact of a warming planet is a complex puzzle that requires interdisciplinary input…

ECS Professor Pankaj K. Jha Receives NSF Grant to Develop Quantum Technology

Detecting single photons—the smallest unit of light—is crucial for advanced quantum technologies such as optical quantum computing, communication and ultra-sensitive imaging. Superconducting nanowire single-photon detectors (SNSPDs) are the most efficient means of detecting single photons and these detectors can count…

Rock Record Illuminates Oxygen History

Several key moments in Earth’s history help us humans answer the question, “How did we get here?” These moments also shed light on the question, “Where are we going?,” offering scientists deeper insight into how organisms adapt to physical and…

Subscribe to SU Today

If you need help with your subscription, contact sunews@syr.edu.

Connect With Us

  • X
  • Facebook
  • Instagram
  • Youtube
  • LinkedIn
Social Media Directory

For the Media

Find an Expert Follow @SyracuseUNews
  • Facebook
  • Instagram
  • Youtube
  • LinkedIn
  • @SyracuseU
  • @SyracuseUNews
  • Social Media Directory
  • Accessibility
  • Privacy
  • Campus Status
  • Syracuse.edu
© 2025 Syracuse University News. All Rights Reserved.