title: C-terminal domain of gyrase A is predicted to have a beta-propeller structure.
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 beta-strands each in GyrA/ParC sequences, allows us to predict that the GyrA/ParC C-terminal domain folds into a 6-bladed beta-propeller. The prediction rationalizes available experimental data and sheds light on the spatial properties of the largest topoisomerase domain that lacks structural information.
authors.affiliation: Department of Biochemistry, University of Texas Southwestern Medical Center, Texas 75390-9050, USA.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Qi
authors.forename: Jimin
authors.initials: J
authors.lastname: Pei
authors.forename: Nick V
authors.initials: NV
authors.lastname: Grishin
mesh_terms: D000595:Amino Acid Sequence; D018797:Cell Cycle Proteins; D027081:DNA Gyrase / Q000737:chemistry* / Q000502:physiology; D027101:DNA Topoisomerase IV / Q000737:chemistry / Q000502:physiology; D020662:Guanine Nucleotide Exchange Factors / Q000737:chemistry; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009687:Nuclear Proteins; D017510:Protein Folding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D015203:Reproducibility of Results; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
chemical_list: D018797:Cell Cycle Proteins; D020662:Guanine Nucleotide Exchange Factors; D009687:Nuclear Proteins; D027101:DNA Topoisomerase IV; D027081:DNA Gyrase