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Probing Structure-Function Relationships of Human Peroxidases

Project management Furtmüller Paul Georg
organizational unit Institute of Biochemistry
duration 01.10.2002 to- 30.09.2005
Research project (§ 26 & § 27)
Program none
Funder Austrian Science Fund (FWF)
Competencies 

Abstract

The homologous mammalian peroxidase superfamily II includes myeloperoxidase (MPO), eosinophil peroxidase (EPO), lactoperoxidase (LPO), and thyroid peroxidase (TPO). MPO and EPO (located in granules of neutrophils and eosinophils, respectively) and LPO (found in secretion fluids such as milk and saliva) play a central role in the antimicrobial defense system, whereas TPO is involved in the biosynthesis of thyroid hormones. MPO and EPO have also been implicated in promoting tissue damage in numerous inflammatory diseases. Despite the physiological relevance and molecular and enzymatic peculiarities of human peroxidases, a comprehensive study of the specific role of individual amino acids in the formation and reactivity of redox intermediates involved in catalysis is still missing. This will be done in this project, which combines the genetic experience of Nicole Moguilevsky's group (who has been successful in the production of unprocessed recombinant MPO and mutants from Chinese hamster ovary cell lines) and of our group (who has been successful in the massive purification of mature MPO and EPO from human blood as well as in establishing protocols for transient kinetic investigations of these enzymes). Based on our recent common paper (Furtmüller et al., FEBS Lett. (2001) 503, 147-150) that the recombinant unprocessed monomeric MPO shows essentially the same kinetic behaviour as the mature dimeric protein, as well as on the known structure of MPO and theoretical models for both EPO and LPO, the production of about 40 mutants of recombinant MPO is suggested. The effect of mutation on ligand binding, redox properties and formation, stability and reactivity of compounds I and II will be investigated in order to answer the following questions: What is the effect of the extraordinary nature of the heme (and its covalent and non-covalent interactions with the protein) on the reactivity of the individual enzyme intermediates and in consequence on the different substrate specificity of MPO, EPO and LPO? What controls the redox properties of the ferric protein and of compounds I and II? What is the actual halide binding site? What controls the potential interaction and reactivity towards organic one-electron donors? What is the proton balance in compound I and II reduction and why is compound II reduction (in contrast to compound I reduction) of human peroxidases strongly constrained by the nature of the substrate? What is the physiological role and the actual site of protein radical formation observed with human peroxidases?

Publications

Project staff

Portrait Paul Georg Furtmüller

Paul Georg Furtmüller

ao.Univ.Prof. Dipl.-Ing.Dr.nat.techn. Paul Georg Furtmüller
paul.furtmueller@boku.ac.at
Tel: +43 1 47654-77277

Project Leader

01.10.2002 - 30.09.2005

Portrait Walter Jantschko

Walter Jantschko

Dipl.-Ing. Walter Jantschko

Project Staff

01.10.2002 - 30.09.2005

Portrait Christian Obinger

Christian Obinger

Univ.Prof. Mag.rer.nat. Dr.rer.nat. Christian Obinger
christian.obinger@boku.ac.at
Tel: +43 1 47654-10011, 77273

Project Staff

01.10.2002 - 30.09.2005

Portrait Manfred Schwanninger

Manfred Schwanninger

Dipl.-Ing.Dr. Manfred Schwanninger

Project Staff

01.10.2002 - 30.09.2005

Portrait Martina Zederbauer

Martina Zederbauer

Dipl.-Ing. Martina Zederbauer

Project Staff

01.10.2002 - 30.09.2005

BOKU partners

Institute of Biochemistry

role coordinator

External partners

University of Brussels, Applied Genetics

Moguilevsky Nicole

partner