BER Structural Biology and Imaging Resources
Synchrotron, Neutron, and Cryo-EM
U.S. Department of Energy | Office of Science | Office of Biological and Environmental Research

Influence of Chemically Disrupted Photosynthesis on Cyanobacterial Thylakoid Dynamics

The mechanical properties of native and herbicide treated Synechocystissp. PCC 6803 cyanobacterial cells under different illumination conditions. The interthylakoidal distance represents the local length scale where thickness and shape fluctuations are sampled. Red arrows show the direction of increase in flexibility. [Image from Stingaciu et al. 2019; available via a Creative Commons license (CC BY 4.0).] Work was performed at the Neutron Spin Echo spectrometer at the Spallation Neutron Source and the Bio-SANS instrument at the High Flux Isotope reactor.

April 5, 2019

Scientific Achievement
Herbicide treatment effects on the dynamical behavior of cyanobacterial photosynthetic membranes (thylakoids) were measured. Changes in membrane mechanical properties were correlated with their structural organization. This provides an important step in understanding the flexibility of the thylakoids and their active function during energy conversion.

Significance and Impact
This study supports the hypothesis that the proton pressure buildup within the lumenal space during photosynthesis drives dynamical changes in the cyanobacterial thylakoids, that are directly and quantitatively correlated with the mechanical properties of photosynthetic membranes.

Research Details
− Living Synechocystis sp. PCC 6803 cells were studied during light and dark alternating cycles
− Neutron spin echo spectroscopy measured the dynamical properties of the membranes
− Small-angle neutron scattering measured membrane thickness and spacing Influence of Chemically