Max Planck Institute of Biophysics

Scientists reveal how phosphate escapes from actin filaments

Illustration on the cover of the Journal Nature Chemical Biology underlines importance of the discovery

The German Research Foundation recognizes Bonnie J. Murphy and Giulio Malavolta with the Heinz Maier-Leibnitz Prize
 

Researchers observe structural dynamics of ribosomes and their interactions with an anticancer drug
 

Dynamic network in the pores of the nuclear envelope blocks dangerous invaders

Talking with friends, enjoying a concert, talking on the phone on noisy streets – people with hearing problems are often unable to hear things that others can. Tobias Moser aims to make sound accessible to those with hearing disabilities in a whole new way through a new generation of hearing protheses. Known as optical cochlear implants, these devices serve as an example of therapies developed on the basis of fundamental research.

Chlamydomonas reinhardtii, a single-celled green alga, can’t see much at all with its eye composed solely of photosensitive rhodopsin molecules. Yet there is more to algal rhodopsin than one would expect. In recent years, it has triggered a revolution in neurobiology. Ernst Bamberg from the Max Planck Institute of Biophysics in Frankfurt helped make it famous. He is now researching these molecules and developing new variants for basic research and medical applications.

As control units of our cells, nuclei contain and guard our genetic material. Pores in the nuclear membrane form the only gateway in and out of the nucleus, allowing important messenger molecules to pass but blocking dangerous invaders such as pathogens. They thus help the nucleus to communicate with the rest of the cell while protecting the genetic material. Such challenging task requires a complex biological structure that has kept many scientists occupied for over two decades; a jigsaw puzzle with missing pieces that we could now solve to near completion.

Single-particle electron cryo-microscopy (CryoEM) is ideal for determining the high-resolution structure membrane protein complexes that are too unstable or too dynamic for x-ray crystallography. Intact rotary ATPases have resisted crystallization for more than 40 years. However, central aspects of their mechanisms now have become clear thanks to the recent CryoEM based structures of intact, functional ATP synthases. The two best and most informative of these structures, the chloroplast ATP synthase and a mitochondrial ATP synthase dimer, have been shown by our department.

Flavin-based electron bifurcating (FBEB) enzyme complexes play a vital role in obligate anaerobic microorganisms for increasing the efficiency of their energy metabolism. They drive an endergonic reduction by an exergonic one via the same electron donor. The energy coupling is realized by a reduced flavin which transfers via energy splitting one strongly and one weakly reducing electron to two different substrates. How FBEB enzyme complexes are structurally constructed is outlined using the example of two acyl-CoA dehydrogenase/electron-transferring flavoproteins.

Living cells are coated and structured by lipid membranes. We addressed two important questions: how are membranes shaped into their often unusual forms, and how do cells monitor the membrane state? With molecular and coarse-grained simulations, we could show how the proteins Mga2 and Ire1 can sense the state of the endoplasmic reticulum. Also, new insights have been obtained about the fusion of vesicles, the formation of tubular structures in the endoplasmic reticulum, and the induction of autophagosomes aided by the Atg1 complex.

We determined the structure of a complete, dimeric F₁F_o-ATP synthase from mitochondria of the yeast Yarrowia lipolytica by a combination of cryo-electron microscopy (cryo-EM) and X-ray crystallography. The structure resolves 58 of the 60 subunits in the dimer. Horizontal helices of subunit a in F_o wrap around the c-ring rotor, and a total of six vertical helices assigned to subunits a, b, f, i, and 8 span the membrane. Our data explain the structural basis of cristae formation in mitochondria, a landmark signature of eukaryotic cell morphology.