title: Biochemical characterization of Escherichia coli DNA helicase I.
abstract: The gene product of F tral is a bifunctional protein which nicks and unwinds the F plasmid during conjugal DNA transfer. Further biochemical characterization of the Tral protein reveals that it has a second, much lower, Km for ATP hydrolysis, in addition to that previously identified. Measurement of the single-stranded DNA-stimulated ATPase rate indicates that there is co-operative interaction between the enzyme monomers for maximal activity. Furthermore, 18O-exchange experiments indicate that Tral protein hydrolyses ATP with, at most, a low-level reversal of the hydrolytic step during each turnover.
authors.affiliation: Department of Biological Sciences, Carnegie-Mellon University, Pittsburgh, Pennsylvania 15213.
authors.forename: P K
authors.initials: PK
authors.lastname: Dash
authors.forename: B A
authors.initials: BA
authors.lastname: Traxler
authors.forename: M M
authors.initials: MM
authors.lastname: Panicker
authors.forename: D D
authors.initials: DD
authors.lastname: Hackney
authors.forename: E G
authors.initials: EG
authors.lastname: Minkley
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D003227:Conjugation, Genetic; D004265:DNA Helicases / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology*; D029968:Escherichia coli Proteins; D005144:F Factor; D007700:Kinetics; D010100:Oxygen / Q000378:metabolism; D013347:Subcellular Fractions
chemical_list: D029968:Escherichia coli Proteins; D000251:Adenosine Triphosphatases; C027093:TraI protein, E coli; D004265:DNA Helicases; D010100:Oxygen