ISSN:
0952-3499
Keywords:
Chemistry
;
Biochemistry and Biotechnology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Medicine
Notes:
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 (attR) 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 attR in crude extracts. Here we report that the Mu transposase protein also contains a Mu attR 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 attR-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 attR 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 attR, 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.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jmr.300010405
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