Conformational dynamics and structure of biomolecules studied by high precision Förster-Resonance-Energy-Transfer (FRET)

Ideal candidates will have a strong interest in analyzing the structure and conformational dynamics of biomolecules. The main working tool will be fluorescence spectroscopy on the single-molecule and ensemble level. Workplace will be the Heinrich-Heine-University in the group of Prof. Dr. Claus Seidel.

Project 1: Development of single-molecule high-precision FRET
While X-ray crystallography reveals snapshots of biomolecules at atomic resolution, many biomolecules are inherently dynamic. In some cases, low populated conformational states are overlooked or simply not accessible using conventional structural-biology tools. FRET that is considered a low-resolution tool has not yet received much attention in the field. However, recent developments in Prof. Seidel's group have shown the ability to reconstruct protein and nucleic acid structures using high-precision (hp) FRET [Methods in Enzymology 475, 455-514 (2010), J. Am. Chem. Soc. 133, 2463-2480 (2011)]. We propose to use these recent tools ensemble and single-molecule spectroscopy to determine hp-FRET structures of multiple conformational states in biomolecules. A special focus is on detailed characterization and 3D architecture of helical structures. Using all our fluorescence techniques, the 3D structures of two complex biomolecules shall be solved in this project: (1) temperature sensitive regulatory RNA "thermometers" with a varying number of stem loops; (2) Studying helix bending und rotation of transmembrane helices in membrane proteins.

Project 2: Applications of single-molecule high-precision FRET
This project combines the use of single-molecule fluorescence techniques with biochemistry and cell biology. Our special interest in molecular biophysics focuses on the dynamic behavior and the nanomechanics of biologically relevant single molecules, e.g. instrinsic disordered proteins and membrane proteins. New techniques for single molecule spectroscopy have been developed in our group to study issues of structural dynamics in structural biology. Your project involves heterolog expression, fluorescence labeling and biophysical characterization of proteins. Basic knowledge and/or experience in molecular biology and biochemistry is mandatory.

Topic Supervisor: Prof. Dr. Claus Seidel, Institute for Physical Chemistry, Heinrich Heine University Düsseldorf, Seidel Group

For important application information and documents please click here...

Application deadline for this open project: February 20^th 2012.

Structure and function of the Chlamydia adhesins OmcB and Pmp21

Chlamydiae are obligate intracellular bacterial pathogens which cause a variety of important human diseases. Chlamydia trachomatis is the most common bacterial agent of sexually transmitted diseases and is responsible for over 90 million new infections every year worldwide. The C. trachomatis ocular serovars are responsible for trachoma, the major cause of preventable blindness in developing countries. Acute C. pneumoniae infections cause pulmonary diseases (e.g. 10 % of all pneumonia incidents worldwide), whereas the chronic infection is linked to atherosclerosis and artery disease. The chlamydial infection starts with the adhesion of the bacteria to the human cell by binding of bacterial adhesins to eukaryotic receptors.
We have identified and characterised the first chlamydial adhesin proteins which interact with the human cell. The OmcB protein binds to heparan sulfate-like glycosaminoglycan (GAG) structures on the human cell surface. Single amino acids in the GAG-binding domain of OmcB are essential for adhesion to human cells and may determine cell tropism and disease pattern for different C. trachomatis serovars (systemic versus local infection). The second adhesin recently identified consists of a family of 21 related polymorphic membrane proteins (Pmp) unique to Chlamydiae, whose human cell surface receptor has just been identified. Pmp proteins are anchored in the bacterial membrane and their N-termini carry several independent adhesion domains.
Analysis of the three-dimensional structure of the adhesins OmcB and Pmp21 (as prototype) will form the basis for a molecular understanding of the interactions of these proteins with their human receptors and will facilitate identification of small molecule inhibitors.

The ideal candidate will have a background in protein biochemistry and biophysical characterization of proteins. A strong interest in infection biology as well as in structural biology is a prerequisite. Workplace will be the Heinrich Heine University Duesseldorf in the group of Prof. Dr. Johannes Hegemann.

Topic Supervisor: Prof. Dr. Hans Hegemann, Functional Genomics of Microorganisms, Heinrich Heine University Düsseldorf, Hegemann Group

For important application information and documents please click here...

Application deadline for this open project: February 20^th 2012.

Structural studies on molecular interactions of the Disrupted-in-schizphrenia (DISC1) protein

The molecular causes of schizophrenia are still unknown. Recently, based on several genetic studies, the disrupted-in-schizophrenia 1 (DISC1) protein has come into focus for investigating molecular mechanisms of schizophrenia and other mental diseases. Here, structural and quantitative investigations of DISC1 with its interacting centrosomal molecules NDEL1, NDE1, PDE4B and LIS1 are proposed. All proteins, or soluble representative fragments thereof, as well as mutant / polymorphic counterparts will be expressed in Escherichia coli. Structural studies will be attempted by NMR and crystallography for single and complexed proteins and complemented by binding studies with surface plasmon resonance. These investigations will yield insight into the stochiometry and regulation of the interactions in the DISC1/NDEL1/NDE1/LIS1/PDE4B complex, and, through structural determination of binding interfaces, open novel pharmacological targets for these diseases.

The ideal candidate will have a background in protein biochemistry and/or biophysical characterization of proteins. Basic knowledge and/or experience in crystallization and X-ray spectroscopy would be an advantage. A strong interest in structural biology is a prerequisite. We are looking for an enthusiastic and highly motivated individual with fluency in written and spoken English, an open mind for new approaches and a lot of team spirit. Workplace will be the University hospital Duesseldorf.

Topic Supervisor: Prof. Dr. Carsten Korth, Neuropathology, Heinrich Heine University of Düsseldorf Medical School, Korth Group

For important application information and documents please click here...

Application deadline for this open project: February 20^th 2012.

Heise Group Studying interactions of Membrane Proteins with ligands by DNP-enhanced Solid-State NMR Spectroscopy Transmembrane receptors and their interaction with ligand molecules still impose a major challenge upon structural biology: In the membrane-reconstituted state, such proteins are not accessible with liquid-state NMR spectroscopy, and crystallization protocols are far from standard. In the past decade, solid-state NMR spectroscopy has developed into a promising tool for structure elucidation or even determination of immobilized proteins which do not have to be crystalline nor soluble. One of the largest obstackles in solid-state NMR spectroscopy is still the low sensitivity. However, the inherently low sensitivity of nuclear magnetization can be overcome by exploiting the 660 times higher magnetic moment of unpaired electrons for signal enhancement via dynamic nuclear polarization (DNP). In 2012 our group will be equipped with one of the first DNP-spectrometers operating at a proton frequency of 600 MHz, in addition to existing state-of-the art solid-state NMR spectrometers ranging from 600 MHz to 800 MHz. We are investigating several membrane receptors and their interactions with ligands. We also develop techniques tailored to specific questions and signal enhancement, and especially DNP will provide ample opportunities for methods developments. The ideal candidate should have a strong background in Physics and Biochemistry. Basic knowledge and experience in NMR or EPR spectroscopy is an advantage. A strong interest in Physics and structural biology and is a prerequisite. The applicant should be highly motivated, open for new approaches and techniques, and able to tackle demanding challenges. Workplace will be the exquisitely equipped Forschungszentrum Juelich. Topic Supervisor: Prof. Dr. Henrike Heise, Institute of Physical Biology, Heinrich Heine University DüsseldorfHeise Group For important application information and documents please click here... Application deadline for this open project: February 20th 2012.

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