Hi
I suggest the following:
1. Use a 1000A support with a low loading (5-10 micromoles per gram).
These supports are available from ChemGenes. The lower loading enables
higher coupling yields, especially with long oligos.
2. Use milder detritylation conditions to prevent depurination. We use
2% v/v dichloroacetic acid in dichloroethane for long oligos and 5%
dichloroacetic acid for shorter oligos. I wouldn't use trichloroacetic
acid in any synthesis.
3. Double the base deprotection step (if you have time). We do an
overnight heating in ammonium hydroxide, then add more ammonium
hydroxide and heat overnight again.
4. Run the crude product out on a 16% PA/7M urea gel. Use the largest
gel plates available. We use 1.5 mm thick spacers and plates about 40 cm
long. You should be able to easily detect a single band product, even
with a 150 base long sequence.
Bob Lee wrote:
> Hi,
>
> What is the best way of making a 150 bases DNA? Thanks.
>
> Bob
-- Richard T. Pon, University of Calgary Professor, Adjunct, Dept. of Biochemistry & Molecular Biology Director, University Core DNA Services Office: (403) 220-4225; Lab (403) 220-4277; Fax: (403) 283-4907 E-mail: rtpon@ucalgary.ca; www.acs.ucalgary.ca/~DNALAB/index.html 3350 Hospital Drive N.W., Calgary, AB, Canada T2N 4N1Inquiries about service may also be directed to DNALAB@ucalgary.ca
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