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Identification of the membrane component of the anion pump encoded by the arsenical resistance operon of R‐factor R773
Author(s) -
San Francisco M. J. D.,
Tisa L. S.,
Rosen B. P.
Publication year - 1989
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.1365-2958.1989.tb00098.x
Subject(s) - biology , operon , component (thermodynamics) , identification (biology) , computational biology , genetics , gene , botany , physics , escherichia coli , thermodynamics
Summary The arsenical resistance ( ars ) operon of the conjugative R‐factor R773 encodes an ATP‐driven anion extrusion pump, producing bacterial resistance to arsenicals. There are three structural genes, of which the product of the middle gene, arsB , has not previously been identified. From nucleotide sequence data, the ArsB protein is predicted to be a 45577 Dalton hydrophobic protein. A mini‐Mu transposition procedure was used to construct an arsB‐lacZ gene fusion, producing a hybrid ArsB‐β‐galactosidase protein which was localized in the inner membrane. The operon was cloned into a T7 RNA polymerase expression vector. In addition to the previously identified ArsA and ArsC proteins, the cells synthesized an inner membrane protein with an apparent mass of 36 kD identified as the ArsB protein.