A5068906179- Electron Spin Resonance Studies
- Lanthanide and Transition Metal Complexes
- Magnetism in coordination complexes
- Metal complexes synthesis and properties
- Advanced NMR Techniques and Applications
- Enzyme Structure and Function
- Porphyrin Metabolism and Disorders
- Spectroscopy and Quantum Chemical Studies
- Legume Nitrogen Fixing Symbiosis
- DNA and Nucleic Acid Chemistry
- Amino Acid Enzymes and Metabolism
- Electrochemical Analysis and Applications
- Drug Transport and Resistance Mechanisms
- RNA and protein synthesis mechanisms
- Plant Molecular Biology Research
- Cancer Research and Treatments
- Mitochondrial Function and Pathology
- Signaling Pathways in Disease
- Biochemical and Molecular Research
- Plant Pathogenic Bacteria Studies
- Protein Structure and Dynamics
- RNA modifications and cancer
- Streptococcal Infections and Treatments
- HIV Research and Treatment
- Advanced MRI Techniques and Applications
Freie Universität Berlin
2023-2025
Goethe University Frankfurt
2015-2023
Institute of Biophysics
2021
Osaka University
2008-2015
University of Zurich
2014
ETH Zurich
2011-2013
Abstract Membrane proteins may be influenced by the environment, and they unstable in detergents or fail to crystallize. As a result, approaches characterize structures native environment are highly desirable. Here, we report novel general strategy for precise distance measurements on outer membrane whole Escherichia coli cells isolated membranes. The cobalamin transporter BtuB was overexpressed spin‐labeled membranes interspin distances were measured using pulse EPR spectroscopy. A...
Abstract The role of resource availability in determining the incidence masting has been widely studied, but how floral transition and initiation are regulated by level is unclear. We tested hypothesis that stimulated high availabiltiy Fagus crenata based on a new technique, expression analyses flowering genes. isolated F. orthologues FLOWERING LOCUS T , LEAFY APETALA1 confirmed their functions using transgenic Arabidopsis thaliana . monitored gene levels for 5 years detected cycle off...
An unrealized goal in structural biology is the determination of structure and conformational change at high resolution for membrane proteins within cellular environment. Pulsed electron–electron double resonance (PELDOR) a well-established technique to follow changes purified protein complexes. Here we demonstrate first proof concept use PELDOR observe intact cells. We exploit fact that outer usually lack reactive cysteines paramagnetic spin labels entering periplasm are selectively reduced...
Abstract The β-barrel assembly machinery (BAM) mediates the folding and insertion of majority outer membrane proteins (OMPs) in gram-negative bacteria. BAM is a penta-heterooligomeric complex consisting central BamA four interacting lipoproteins BamB, C, D, E. conformational switching between inward-open (IO) lateral-open (LO) conformations required for substrate recognition folding. However, mechanism lateral gating or how structural details observed vitro correspond with cellular...
Abstract The orchestrated interaction of transmembrane proteins with other molecules mediates several crucial biological processes. Detergent solubilization may significantly alter or even abolish such hetero‐oligomeric interactions, which makes observing them at high resolution in their native environment technically challenging. Dipolar electron paramagnetic resonance (EPR) techniques as pulsed electro–electron double (PELDOR) can provide very precise distances within biomolecules. To...
Significance ABC transporters shuttle chemically diverse substances across membranes in an energy-dependent manner. They mediate multidrug resistance microorganisms and cancer cells can cause human pathologies when dysfunctional. Although important insights into have been gained recent years, fundamental questions concerning their mechanism remain open. Here, we identify the protein complex TmrAB as a functional homolog of antigenic peptide transporter TAP present its high-resolution...
Abstract The SLC26 family of transporters maintains anion equilibria in all kingdoms life. shares a 7 + transmembrane segments inverted repeat architecture with the SLC4 and SLC23 families, but holds regulatory STAS domain addition. While only experimental structure is monomeric, proteins form structural functional dimers lipid membrane. Here we resolve an dimer embedded membrane characterize its relevance by combining PELDOR/DEER distance measurements biochemical studies MD simulations...
In situ investigation of membrane proteins is a challenging task. Previously we demonstrated that nitroxide labels combined with pulsed ESR spectroscopy promising tool for this purpose. However, the suffer from poor stability, high background labeling, and low sensitivity. Here show Finland (FTAM) OX063 based enable labeling cobalamin transporter BtuB BamA, central component β-barrel assembly machinery (BAM) complex, in E coli. Compared to methanethiosulfonate spin label (MTSL), trityl...
Increased efforts are being made for observing proteins in their native environments. Pulsed electron–electron double resonance spectroscopy (PELDOR, also known as DEER) is a powerful tool this purpose. Conventionally, PELDOR employs an identical spin pair, which limits the output to single distance monomeric samples. Here, we show that Gd3+–trityl–nitroxide (NO) three-spin system versatile study heterooligomeric membrane protein complexes, even within membrane. This allowed independent...
ATP-binding cassette (ABC) transporters are ubiquitous integral membrane proteins that translocate substrates across cell membranes. The alternating access of their transmembrane domains to opposite sides the powered by closure and reopening nucleotide binding is proposed drive translocation events. Despite clear structural similarities, evidence for considerable mechanistic diversity starts accumulate within importers subfamily. We present here a detailed study gating mechanism type II ABC...
ATP-binding cassette (ABC) exporters actively move chemically diverse substrates across biological membranes. Their malfunction leads to human diseases. Many ABC encompass asymmetric nucleotide-binding sites (NBSs), and some of them are inhibited by the transported substrate. The functional relevance catalytic asymmetry or mechanism for trans-inhibition remains elusive. Here, we investigated TmrAB, a homologue antigen translocation complex TAP using advanced electron–electron double...
Spectroscopic investigation of membrane proteins in their native environment is a challenging task. Earlier we demonstrated the feasibility to measure precise distances within outer E. coli and membranes using methanethiosulfonate (MTS) functionalized labels combined with pulsed electron-electron double resonance spectroscopy. Here show application maleimide Gd(III), nitroxide, trityl for situ distance measurement cobalamin transporter BtuB. These enabled measurements BtuB maleimide-Gd-DOTA...
Macrophage infectivity potentiator (MIP) proteins, found in pro- and eukaryotic pathogens, influence microbial virulence, host cell infection, pathogen replication, dissemination. MIPs share an FKBP (FK506 binding protein)-like prolyl-cis/trans-isomerase domain, making them attractive targets for inhibitor development. We determined high-resolution crystal structures of Burkholderia pseudomallei Trypanosoma cruzi complex with fluorinated pipecolic acid inhibitors. The profiles solution were...
The membrane transporter BtuB is site-directedly spin labelled on the surface of living
Macrophage infectivity potentiator (MIP) proteins are present in many microbial pathogens, both of pro- and eukaryotic origin. MIP play important roles virulence, facilitating processes like host cell infection, pathogen replication dissemination. While their domain architecture differs MIPs, they all share a FKBP (FK506 binding protein)-like prolyl-cis/trans-isomerase domain. Due to its high conservation, the has been target for inhibitor development, including pipecolic acid derivatives....
Root parasitic weeds in Orobanchaceae cause serious damage to worldwide agriculture. Germination of the parasites requires host-derived germination stimulants, such as strigolactones, indicators host roots within reach parasite's radicles. This unique process was focused on identify metabolic pathways required for germination, and design a selective control strategy. A metabolomic analysis germinating seeds clover broomrape, Orobanche minor, conducted its distinctive metabolites....
Abstract Membrane proteins may be influenced by the environment, and they unstable in detergents or fail to crystallize. As a result, approaches characterize structures native environment are highly desirable. Here, we report novel general strategy for precise distance measurements on outer membrane whole Escherichia coli cells isolated membranes. The cobalamin transporter BtuB was overexpressed spin‐labeled membranes interspin distances were measured using pulse EPR spectroscopy. A...
The β-barrel assembly machinery (BAM) consisting of the central BamA and four other lipoproteins mediates folding majority outer membrane proteins. is placed in an asymmetric bilayer its lateral gate suggested to be functional hotspot. Here we used situ pulsed electron-electron double resonance spectroscopy characterize native membrane. In detergent micelles, data consistent with mainly inward-open conformation BamA. considerably enhanced conformational heterogeneity. extracellular loop 3...
Abstract The orchestrated interaction of transmembrane proteins with other molecules mediates several crucial biological processes. Detergent solubilization may significantly alter or even abolish such hetero‐oligomeric interactions, which makes observing them at high resolution in their native environment technically challenging. Dipolar electron paramagnetic resonance (EPR) techniques as pulsed electro–electron double (PELDOR) can provide very precise distances within biomolecules. To...
ATP-binding cassette (ABC) transporters shuttle diverse substrates across biological membranes. Transport is often achieved through a transition between an inward-facing (IF) and outward-facing (OF) conformation of the transmembrane domains (TMDs). Asymmetric nucleotide-binding sites (NBSs) are present among several ABC subfamilies their functional role remains elusive. Here we addressed this question using concomitant NO-NO, Mn2+ -NO, -Mn2+ pulsed electron-electron double-resonance...