C-terminal domain of gyrase A is predicted to have a β-propeller structure

Authors

  • Yuan Qi,

    1. Department of Biochemistry, University of Texas Southwestern Medical Center, Texas
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  • Jimin Pei,

    1. Department of Biochemistry, University of Texas Southwestern Medical Center, Texas
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  • Nick V. Grishin

    Corresponding author
    1. Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas
    2. Department of Biochemistry, University of Texas Southwestern Medical Center, Texas
    • Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390-9050
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Abstract

Two different type II topoisomerases are known in bacteria. DNA gyrase (Gyr) introduces negative supercoils into DNA. Topoisomerase IV (Par) relaxes DNA supercoils. GyrA and ParC subunits of bacterial type II topoisomerases are involved in breakage and reunion of DNA. The spatial structure of the C-terminal fragment in GyrA/ParC is not available. We infer homology between the C-terminal domain of GyrA/ParC and a regulator of chromosome condensation (RCC1), a eukaryotic protein that functions as a guanine-nucleotide-exchange factor for the nuclear G protein Ran. This homology, complemented by detection of 6 sequence repeats with 4 predicted β-strands each in GyrA/ParC sequences, allows us to predict that the GyrA/ParC C-terminal domain folds into a 6-bladed β-propeller. The prediction rationalizes available experimental data and sheds light on the spatial properties of the largest topoisomerase domain that lacks structural information. Proteins 2002;47:258–264. © 2002 Wiley-Liss, Inc.

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