This project aims to unravel the three-dimensional structures as well as the mode of operation of two DNA-binding proteins: diphtheria toxin repressor from Corynebacterium diphtheria, the causative agent of diphtheria, and human topoisomerase I. The key question to be addressed regarding diphtheria toxin repressor is its regulation of sequence-specific DNA-recognition by transition metals, in particular Fe2+. No three-dimensional structures of metal-regulated repressors are known yet, hence the goal is to elucidate crystal structures of the repressor in complex with duplex DNA and a series of transition metal ions. Fe-dependent repressors play an important role in many pathogenic bacteria, such as Shigella dysentheriae and Vibrio cholerae, where they control the role in many pathogenic bacteria, such as Shigella dysentheriae and Vibrio cholerae, where they control the expression of several virulence factors. Consequently, the three dimensional structure of diphtheria toxin repressor will be a starting point for the design of small molecules which will enhance the affinity of the repressor for the operator, Such molecules not only prevent the production of toxin but also impede the growth of bacteria by suppressing the production of other proteins which are essential for pathogen. Human topoisomerase I is important for maintaining the proper higher order topology of DNA during transcription, replication and recombination. The specific goals are to elucidate the three-dimensional crystal structures of the enzyme, wild type and mutants, with and without DNA bound, in the presence of several inhibitors. The results provide a firm basis for unraveling the complicated catalytic mechanism of the enzyme and for understanding the mode of action of a wide variety of inhibitors. Several of these topoisomerase I poisons ar e of the greatest interest as they have very promising properties for the treatment of a wide variety of cancers. In addition, the crystal structure of human topoisomerase I will form an excellent basis for the design of new inhibitors which ar potential new cancer drugs.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
1R01CA065656-01
Application #
2108719
Study Section
Molecular and Cellular Biophysics Study Section (BBCA)
Project Start
1995-03-01
Project End
1999-12-31
Budget Start
1995-03-01
Budget End
1995-12-31
Support Year
1
Fiscal Year
1995
Total Cost
Indirect Cost
Name
University of Washington
Department
Anatomy/Cell Biology
Type
Schools of Medicine
DUNS #
135646524
City
Seattle
State
WA
Country
United States
Zip Code
98195
Wisedchaisri, Goragot; Wu, Meiting; Sherman, David R et al. (2008) Crystal structures of the response regulator DosR from Mycobacterium tuberculosis suggest a helix rearrangement mechanism for phosphorylation activation. J Mol Biol 378:227-42
Wisedchaisri, Goragot; Chou, C James; Wu, Meiting et al. (2007) Crystal structures, metal activation, and DNA-binding properties of two-domain IdeR from Mycobacterium tuberculosis. Biochemistry 46:436-47
Davies, Douglas R; Mushtaq, Adeel; Interthal, Heidrun et al. (2006) The structure of the transition state of the heterodimeric topoisomerase I of Leishmania donovani as a vanadate complex with nicked DNA. J Mol Biol 357:1202-10
Wisedchaisri, Goragot; Wu, Meiting; Rice, Adrian E et al. (2005) Structures of Mycobacterium tuberculosis DosR and DosR-DNA complex involved in gene activation during adaptation to hypoxic latency. J Mol Biol 354:630-41
Chou, C James; Wisedchaisri, Goragot; Monfeli, Ryan R et al. (2004) Functional studies of the Mycobacterium tuberculosis iron-dependent regulator. J Biol Chem 279:53554-61
Wisedchaisri, Goragot; Holmes, Randall K; Hol, Wim G J (2004) Crystal structure of an IdeR-DNA complex reveals a conformational change in activated IdeR for base-specific interactions. J Mol Biol 342:1155-69
Quigley, Paulene M; Korotkov, Konstantin; Baneyx, Francois et al. (2004) A new native EcHsp31 structure suggests a key role of structural flexibility for chaperone function. Protein Sci 13:269-77
Davies, Douglas R; Interthal, Heidrun; Champoux, James J et al. (2004) Explorations of peptide and oligonucleotide binding sites of tyrosyl-DNA phosphodiesterase using vanadate complexes. J Med Chem 47:829-37
Sastry, M S R; Quigley, Paulene M; Hol, Wim G J et al. (2004) The linker-loop region of Escherichia coli chaperone Hsp31 functions as a gate that modulates high-affinity substrate binding at elevated temperatures. Proc Natl Acad Sci U S A 101:8587-92
Davies, Douglas R; Interthal, Heidrun; Champoux, James J et al. (2003) Crystal structure of a transition state mimic for Tdp1 assembled from vanadate, DNA, and a topoisomerase I-derived peptide. Chem Biol 10:139-47

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