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Biochemical characterization of Escherichia coli DNA helicase I
Author(s) -
Dash Pramod K.,
Traxler Beth A.,
Panicker Mitradas M.,
Hackney David D.,
Minkley Edwin G.
Publication year - 1992
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.1992.tb01555.x
Subject(s) - biology , escherichia coli , helicase , dna , microbiology and biotechnology , computational biology , genetics , gene , rna
Summary 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, K m 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, 18 O‐exchange experiments indicate that Tral protein hydrolyses ATP with, at most, a low‐level reversal of the hydrolytic step during each turnover.