no ligation of compatible fragments?

[Wenqing Liang]

Is it true that low NaCl concentration increases BamHi star activity? 
John K. Troyer (jtroyer at umabnet.ab.umd.edu) wrote:
: On Fri, 13 Oct 1995, Michael Szardenings wrote:

: > Hi,
: > I have had some problems cloning fragments into a vector. Finally I
: > checked some restriction enzymes by trying to cleave and religate lambda
: > DNA. This did not work for our SmaI and BamHI, but worked well for other
: > enzymes like HindIII etc.
: > SmaI might be artefact, although I have done blunt end ligation under
: > similiar conditions before, BamHI is definitely not and SmaI/BamHI is just
: > the cloning I am trying. Enzymes are from BRL, so not just 'some'
: > supplier, but they have spent a while in the freezer. Nevertheless, I have
: > never seen something like this.
: > Can enzymes really get 'unspecific', i.e. give different types of cuts on
: > the same recognition sequence?
: > 
: > All ideas are wellome
: >                         Michael




: Michael:

: How long are you digesting and how much Bam are you using?   Bam HI has 
: star activity which may cause problems if you either digest for too long 
: or your RE concentration is too high.


: Regards,

: John

: ***************************************************
: John K. Troyer, PhD
: University of Maryland School of Medicine
: Department of Biological Chemistry
: jtroyer at umabnet.ab.umd.edu
: ***************************************************