Institut für Molekulare Biowissenschaften
Forschungsthemen
| Lehrstuhl | Anrede | Vorname | Nachname | ||||
Prof. | Richard | ||||||
Prof. | Jörg | ||||||
Prof. | Gerhard | ||||||
Prof. | Helge | ||||||
Prof. | Heinz Dieter | ||||||
Prof. | Volker | ||||||
| Molekulare Mikrobiologie und Bioenergetik | Prof. | Beate | |||||
Prof. | Enrico | ||||||
Dr. | Andreas | ||||||
Prof. | Claudia | ||||||
Prof. | Eckhard | ||||||
Prof. | Jens |
Hochschullehrer
| Anrede | Vorname | Nachname | Lehrstuhl | ||||
Prof. | Beate | ||||||
Prof. | Helge | ||||||
Prof. | Eckhard | ||||||
Prof. | Claudia | ||||||
Prof. | Volker | ||||||
Prof. | Heinz Dieter | ||||||
Prof. | Gerhard | Biosynthese in Pflanzen und Mikroorganismen | |||||
Prof. | Enrico | ||||||
Dr. | Andreas | ||||||
Prof. | Jörg | ||||||
| Prof. | Richard | ||||||
Prof. | Jens |
Kolloquium
Sommersemester 2020
Die Vorträge finden jeweils um 17:15 Uhr statt. The talks starts at 17:15.
Ort: Biozentrum auf dem Campus Riedberg, Raum 260/3.13
Where: Campus Rieberg, Biocenter, Section of the Building 260 Room 3.13
Thursday, 12.03.2020 - Dr. Jan Schuller - MPI für Biochemie, Martinsried
Modular Evolution and Functional Adaption of the Photosynthetic Complex I
The cyanobacterial carbon concentration mechanism takes advantage of the functional and structural diversity of the cyanobacterial photosynthetic NADH dehydrogenase-like complex I (NDH-1) that function as energy-converting ferredoxin plastoquinone oxidoreductases. A distinguishing feature of the cyanobacterial NDH-1 complexes is their role in CO2 hydration. Specialized forms of the NDH-1 complex, the NDH-1MS and NDH-1MS’ complexes, contain alternative subunits that drive the conversion of CO2 to HCO3- against the equilibrium using redox energy supplied by ferredoxin. Using cryo-EM single particle analysis we could obtain the first structure of a carbon concentrating NDH-1 complex. Our structure reveals a novel catalytic carbonic anhydrase (CA) module that possess a unique active site harbouring a Zn2+ ion ligated in a different way compared to the well-known α and ß CAs. Supported by theoretical calculations we demonstrate that the propagation of the proton translocation along the membrane part of the complex facilitates the removal of the proton that is released by the CO2 hydration. Unexpectedly, we found that the terminal anti-porter like subunit NdhF3 is not a functional proton pump, but instead harbours a hydrophobic channel that might enable the flow of CO2 molecules directly to the active site of CupA. Taken all this together we present a mechanistic model in which the out of equilibrium CO2 hydration is driven by a push- and pull mechanism.
05.05.2020 - Dr. Danny Ionescu - Leibniz Institut Stechlin
Achromatium oxaliferum - A compartmentalized super bacterium with multiple-personalities
Polyploid bacteria are common, but the genetic and functional diversity resulting from polyploidy is not fully understood. Achromatium sp. is the largest freshwater bacterium. Its cells contain multiple calcite bodies whose evolutionary role has not been determined. Like other large-sulfur bacteria, it has multiple chromosomes as seen by nucleic acid staining. Using single-cell genomics, metagenomics, single- cell amplicon sequencing and fluorescence in-situ hybridization, we show that individual cells Achromatium harbor genetic diversity typical of multi-species populations. Interestingly, the rRNA distribution inside the cells hints to spatially- differential gene expression. Broad-scale surveys of short-read archives show that Achromatium sp. is globally present in rivers, freshwater lakes, and marine environments but no environment-specific phylogenetic clustering of the 16S rRNA gene is observed. This is likely due to high intra-cellular and population-wide phylogenetic diversity further supporting our findings. We show that these cells contain and also express tens of transposable elements, which likely contribute the unprecedented diversity that we observe in the sequence and synteny of genes. Accordingly, we suggest that the multiple chromosomes of Achromatium do not represent copies of its genome. Nevertheless, our analysis shows that most proteins are under conservation pressure. Thus, given the high single-cell diversity of functional genes and the usually conserved 16S rRNA gene, we suggest that gene convergence is limited to chromosomal clusters formed by the large calcite bodies in the cell. We further suggest that upon cell division, these cluster are shuffled resulting in two daughter cells different from each other as well as from the mother cell. To obtain information on how many alleles of a gene are expressed from the complete repertoire available in each cell, we are developing a method to simultaneously obtain both the genome and transcriptome of each single cell. This allows overcoming the lack of a common genome sequence to the entire population.
