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A subsequence‐specific DNA‐binding domain resides in the 13 kDa amino terminus of the bacteriophage Mu transposase protein
Author(s) -
Tolias Peter P.,
DuBow Michael S.
Publication year - 1989
Publication title -
journal of molecular recognition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.401
H-Index - 79
eISSN - 1099-1352
pISSN - 0952-3499
DOI - 10.1002/jmr.300010405
Subject(s) - transposase , bacteriophage mu , biology , bacteriophage , dna , microbiology and biotechnology , fusion protein , n terminus , dna binding domain , peptide sequence , recombinant dna , gene , biochemistry , transposable element , transcription factor , escherichia coli , genome
We have previously reported that the 13kDa amino terminus of the 70 kDa bacteriophage D108 transposase protein ( A gene product) contains a two‐component, sequence‐specific DNA‐binding domain which specifically binds to the related bacteriophage Mu's right end ( att R) in vitro . To extend these studies, we examined the ability of the 13 kDa amino terminus of the Mu transposase protein to bind specifically to Mu att R in crude extracts. Here we report that the Mu transposase protein also contains a Mu att R specific DNA‐binding domain, located in a putative α‐heix‐turn‐α‐helix region, in the amino terminal 13 kDa portion of the 70 kDa transposase protein as part of a 23 kDa fusion protein with β‐lactamase. We purified for this att R‐specific DNA‐binding activety and ultimately obtained a single polypeptide of the predicated molecular weight for the A ′—′bla fusion protein. We found that the pure protein bound to Mu att R site in a different mannar compared with the entrie Mu tranposase protein as determined by DNase I‐footpriting. Our results may suggest the presence of a potential of a potential primordial DNA‐binding site (5′‐PuCGAAA‐3′) located several times within att R, at the ends of Mu and D108 DNA, and at the extremities of other prokaryotic class II elements that catalyze 5 base pair duplications at the site of element insertion. The dissection of the functional domains of the related phage Mu and D108 transposase provide clues to the mechanism and evolution of DNA transposition as a mode of mobile gentic element propagation.