Mr. Thomas Classen

Pietruzszka Group Institute of Bioorganic Chemistry Research Center Jülich GmbH Stetternicher Forst, Building 15.8 Room 212 52426 Jülich, Germany  +49(0)2461-613745  +49(0)2461-616196

Mini Academic CV

University degrees:

First degree or intermediate examination:

• Bachelor of Science (Biochemistry), 2007, Heinrich-Heine-University Düsseldorf, Germany

Second degree and/or intermediate examination:

• Master of Science (Biochemistry), 2009, Heinrich-Heine-University Düsseldorf, Germany

BioStruct PhD project

Structure Based Design of Aldolases
Pyruvate dependent aldolases catalyze the aldol reaction between pyruvate or phosphoenolpyruvate and an acceptor molecule. The reaction type is difficult to realize with conventional synthetic methods especially when control of stereoselectivity is required. In contrast to this, enzymes catalyze the transformation allowing mild reaction conditions (ambient temperature and pressure) and do often have high stereo-, regio- and chemoselectivity. However, there are still several challenges when using enzymes in preparative scale:

1. Non-natural substrates are often not acceptable and might even inhibit the enzyme.
2. The reaction partner (the carbonyl component) should sterically not be demanding.
3. The selectivity should be high; however, both enantiomeric products should be accessible via the biocatalytic approach.
4. The process should be scalable.

Wild-type aldolases are available, but do not meet all requirements for the envisaged synthesis project. Since crystallographic data for the aldolase in question are available, a structure-based design of catalysts is feasible. The following concept is pursued:

1. A high throughput screening assay (activity and selectivity) is currently established.
2. The wild-type enzyme is currently produced to verify the assay.
3. As a starting point for the PhD project, (in silico) docking experiments (Gohlke) based on the X-ray structure should allow suggesting sites for mutagenesis.
4. The designed library will be evaluated with the assay; it will be attempted to crystallize the new catalysts (Groth) thus generating a sound basis for further rounds of evolution and underpinning the in silico data.
5. Best 'hits' will be evaluated for transformations in preparative scale.

Topic Supervisor: Prof. Dr. Jörg Pietruszka, Institute of Bioorganic Chemistry, Research Center Jülich GmbH, Pietruszka Group

Complementary Supervisor: Prof. Dr.Georg Groth, Institute for Plant Biochemistry, Heinrich Heine University Duesseldorf, Groth Group

Complementary Supervisor: Prof. Holger Gohlke, Institute of Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Duesseldorf, Gohlke Group

BioStruct Fellow: Mr. Thomas Classen