Journal article
Backbone Dynamics of the C-Terminal Domain of Escherichia coli Topoisomerase I in the Absence and Presence of Single-Stranded DNA
Biochemistry (Easton), Vol.35(30), pp.9661-9666
07/30/1996
DOI: 10.1021/bi960507f
PMID: 8703937
Abstract
The backbone dynamics of the C-terminal DNA-binding domain of Escherichia coli topoisomerase I has been characterized in the absence and presence of single-stranded DNA by NMR spectroscopy. 15N spin-lattice relaxation times (T 1), spin-spin relaxation times (T 2), and heteronuclear NOEs were determined for the uniformly 15N-labeled protein. These data were analyzed by using the model-free formalism to derive the model-free parameters (S 2, τ(e), and R(ex)) for each backbone N-H bond vector and the overall molecular rotational correlation time (τ(m)). The molecular rotational correlation time τ(m) was determined to be 7.49 ± 0.36 ns for the free and 12.7 ± 1.07 ns for the complexed protein. Several residues were found to be much more mobile than the average, including 11 residues at the N-terminus, 2 residues at the C-terminus, and residues 25 and 31-35 which are located in a region of the protein that binds to DNA. The binding of ssDNA to the free protein causes a slight increase in the order parameters (S 2) for a small number of residues and a slight decrease in the order parameters (S 2) for the majority of the residues. In particular, upon binding to ssDNA, the mobility of the first α-helix and the two β-sheets was slightly increased, and the mobility of a few specific residues in the loops/turns was restricted. These results differ from the previous studies on the backbone dynamics of molecular complexes in which reduced mobilities were typically observed upon ligand binding.
Details
- Title: Subtitle
- Backbone Dynamics of the C-Terminal Domain of Escherichia coli Topoisomerase I in the Absence and Presence of Single-Stranded DNA
- Creators
- Liping Yu - New York Medical CollegeChang-Xi Zhu - New York Medical CollegeYuk-Ching Tse-Dinh - Pharmaceutical Discovery Division, D47G, AP10, Abbott Laboratories, Abbott Park, Illinois 60064, and Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, New York 10595Stephen W. Fesik - New York Medical College
- Resource Type
- Journal article
- Publication Details
- Biochemistry (Easton), Vol.35(30), pp.9661-9666
- DOI
- 10.1021/bi960507f
- PMID
- 8703937
- ISSN
- 0006-2960
- eISSN
- 1520-4995
- Language
- English
- Date published
- 07/30/1996
- Academic Unit
- Biochemistry and Molecular Biology; Medicine Administration
- Record Identifier
- 9984627341402771
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