| Autor: |
McGeoch MW; PLEX Corporation, 275 Martine St., Suite 100, Fall River, Massachusetts 02723, USA., Owen RL; Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom., Jaho S; Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom., McGeoch JEM; Department of Molecular and Cellular Biology, Harvard University, 52 Oxford St., Cambridge, Massachusetts 02138, USA. |
| Abstrakt: |
Hemoglycin, a 1494 Da polymer composed of iron and glycine, has been detected in several carbonaceous meteorites. Iron atoms close out the ends of a 5 nm anti-parallel glycine beta sheet and contribute visible and near infrared absorptions that are not present with glycine alone. The 483 nm absorption of hemoglycin was discovered in theory and then observed on beamline I24 at Diamond Light Source. Light absorption in a molecule involves a coupled lower set of states receiving light energy that causes a transition into an upper set of states. In the reverse process, some energy source, such as an x-ray beam, populates the upper set of molecular states, which then radiates light as it returns to the lower "ground" set of states. We report on visible light re-emission during x-ray irradiation of a hemoglycin crystal. The emission is dominated by bands centered at 489 and 551 nm. |
