phage display using Stratagene's Surfzap Kit

tera tjstbc at
Tue Mar 19 11:34:53 EST 1996

Hi Alex, 
		We have used Gigapack II as well and haven't noticed any major drop 
off in packaging efficiencies so I'm pretty sure that's not a problem.  
I have recently begun setting up ligations based on pmol ends rather 
than nanogram ratios and this may contribute to more efficient 
ligations. Generally, I have been using 2:1-4:1 insert to arms ratio of 
available pmol ends in ligation rxns.  The equation for this calc. that 
I have used for linear DNA is:

		2(N+1) x 10E6/molecular wt. daltons where N=number of restriction 
sites. 660=mol. wt. 1 base pair.

	so, given that stratagene includes a test insert (1.4Kb TT binding fAB) 
and suggests ligating 1uL (.25 ug) with 1.0 ug arms, this would work out 
to an 8:1 ratio (ie pmol ends insert= 2(2+1)x 10E6/ 1400x660 
=6x10E6/9.2x10E5 = 6.5pmol ends/ug or 1.6pmol ends/250ng.  Stratagene 
suggests combining this with 1 ug arms or ~0.2pmol ends for an 8:1 
ratio.  I have been keeping, however, to the 2:1-4:1 range with 
satisfactory results.  Does any of this gibberish make sense? Hope it 
helps. Good luck and happy cloning. Barry.

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