The SFB 1078 kindly invites you to the following colloquium talks:

1. Dr. Kirill Kovalev hosted by Joachim Heberle (FUB):

Title: 4D crystallography of microbial rhodopsins

Abstract: Microbial rhodopsins constitute a large superfamily of light-sensitive membrane proteins. They allow small organisms to utilize solar energy for their survival. Upon light illumination microbial rhodopsins undergo a photocycle – a series of transformations through several metastable intermediates – finally returning to the initial dark state. The transitions within the photocycle last from femtoseconds up to seconds and dictate the function of the rhodopsin. Determination of the high-resolution structures of not only the ground, but also of intermediate states of microbial rhodopsin photocycle is vital for understanding of its molecular mechanism. In the talk I will present our latest results obtained with 4D crystallography approach, including time-resolved serial millisecond crystallography, for the studies of various microbial rhodopsins, such as light-driven sodium and inward proton pumps. I will also describe our recent experience in use of single-particle cryo-electron microscopy as a complementary technique for the structural investigations of rhodopsins.

2. Prof. Frauke Gräter hosted by Prof. Ulrike Alexiev (FUB):

Title: A protein material or a mega-enzyme? How collagen tames proton-coupled electron transfer

Abstract: Proteins like collagen are perpetually subjected to mechanical forces. We have known for nearly a century that high mechanical load on polymer materials - be it a shoe sole or rubber band – causes the rupture of chemical bonds and generates mechanoradicals. We uncovered the very same mechanism in biology: radicals form by stretching collagen, the major protein material of our body [1]. Using experiments in conjunction with simulations and machine learning we show how collagen tames its radicals and converts them to oxidative stress. Mechanically produced radicals rapidly migrate, through controlled protein-coupled electron transfer reactions, to specific amino acids in collagen that stabilize the radicals and thereby act as radical sinks [2]. We propose mechanoradicals and their transfer reactions in collagen as a theme potentially involved in tissue ageing and disease. 

[1] Rennekamp et al, Nat Comm, in press, 2023, https://www.biorxiv.org/content/10.1101/2022.10.17.512491v2

[2] Kurth et al, Angewandte, in press, 2023, https://onlinelibrary.wiley.com/doi/10.1002/anie.202216610