The preparation of synthetic RNA has a number of limitations. The TBS group is not 100% stable to the basic conditions used to removed the tert-butylphenoxyacetyl protecting groups, and loss of the TBS group at this stage can lead to phosphodiester chain cleavage and (more seriously) 3′- to 2′-phosphate migration. Fast Deprotection of Synthetic Oligodeoxyribonucleotides Using Standard Reagents under Microwave Irradiation. Slow and manual task (Ti et al., 1982; Caruthers et al. The synthesis of.
The DNA Synthesis Service uses the MerMade-192 synthesizer from BioAutomation. The MerMade has the capability to synthesize up to 192 oligos in a single run. A full run of 20-mers can be completed overnight. These oligos are suitable for a wide range of applications including PCR, dye terminator sequencing, cloning, microarray experiments, hybridization, reverse transcriptase PCR, and custom gene synthesis. Oligos up to 120 bases in length can been made with a coupling efficiency in excess of 98%. Oligos are synthesized in individual columns in a 96-well format. Cleavage and deprotection are done off instrument. Purification and other post processing steps are done robotically to ensure rapid, accurate and consistent processing of oligo orders. Most orders placed for 50-nmol oligos (up to 70 bases in length) will be available for pickup the next working day. Orders for 200-nmol scale, and for very long oligos, may take additional time.
Scale
Two synthesis scales are available, 50-nmol and 200-nmol. The 50-nmol scale is usually sufficient for clients using the oligos for sequencing or PCR. A single OD of an oligo is typically good for thousands of sequencing or PCR reactions (see expected yield information below). The 200-nmol scale is available for clients who need to run the same assay or reaction very frequently.
Please Note: Due to the small number of 200-nmol scale oligo orders, we will be processing all 200-nmol scale orders on Wednesdays.
Purification
All oligos synthesized at the facility are desalted with a Sephadex column to remove ammonium ions and deprotection by-products at no extra charge. Additional purification is available using Varian's TOP: Trityl On Oligonucleotide Purification System at an additional charge. This is sometimes referred to as cartridge, OPC or reverse phase purification. Oligos to be purified via the TOP method are synthesized with the 5' terminus protecting group (trityl or dimethoxyltrityl (DMT)) left on. The hydrophobic nature of the trityl group permits tighter retention of the desired full-length oligo than the truncated failure sequences that do not contain a trityl group. Failure sequences are washed from the tube with a low percent acetonitrile rinse. Retained oligos are detritylated on-column with trifluoroacetic acid to remove the acid-labile trityl group. Residual acid is rinsed from the column and the full-length oligo is recovered with an acetonitrile/water solution. Oligos purified in this way are greater than 90% pure full-length oligo.
Yield
Yield is affected by oligo base composition and length. In general you can expect the following yields for an average 20-mer:
Please note that for purified oligos, yield will decrease with increased oligo length. Oligos that do not meet minimum yield standards will be resynthesized at no additional charge. For particularly difficult oligos you may receive the product of several syntheses to achieve an acceptable final total yield.
Specialty Reagents
The facility provides inosine at no additional cost. Clients desiring fluorescent tags or other modifications should contact the facility to determine availability and cost. Most modifications that use standard phosphoramidite chemistry may be made on the MerMade. Please be aware that these reagents are usually packaged in such a way that a single bottle provides enough for several modifications. Once a bottle of specialty reagent is opened, it has a limited stability. Due to this, we must charge for an entire bottle of reagent no matter how many oligos are actually modified. For this reason, it may not be cost effective to label only a small number of oligos. It may be better to pool orders with other researchers or save up oligos until the bottle can be used efficiently. The client will be charged for any specialty reagents plus the usual per base charge.
Ordering Instructions
Standard Bases
Mixed Bases
Specialty Bases / Modifications 1
(Others available on request. Please contact the facility)
Apple iphone 6 plus user manual free download. 1 - The MerMade is limited to a total of 6 different specialty or different
mixed base positions in a single oligo or run 2 - Additional Reagent Charges 3 - TET is not supported for Genotyping on our newer Applied Biosystems instruments. Sequencing Primers
If you need custom primers synthesized for your sequencing job, the facility can make it fast and simple to coordinate your order and eliminate the need for multiple or delayed shipments of samples. When ordering custom primers for sequencing at our facility, you must place your sequencing order prior to submitting your primer synthesis order.
Please follow these steps when ordering custom primers for sequencing:
Once your primer synthesis order is complete, our facility will automatically make a primer dilution and start your sequencing order. Your primer stock(s) will be available for pickup once your sequencing order is complete. The primer tracking number(s) are required for pickup your custom primer(s). Please pickup your custom primer stock(s) as soon as possible once they are done. If you do not pick up your primer stock(s), they will be kept at the facility for a limited period of time and then we will dry them down and mail them to the address on file in your profile.
Cobb accessport v3 focus st user manual. To reconstitute a primer stock(s) that has been dried down after being used for sequencing:
For help with primer design, please see our 'Designing Custom Primers page. The facility also provides a primer design and primer walking service. Additional information can be found on our Primer Walking service page.
An Overview of Chemical DNA Synthesis
DNA synthesis is a cyclical process that assembles a chain of nucleotides from the 3'-end to the 5'-end. The 3' nucleoside is covalently attached to a solid support and successive nucleotide monomers are added one by one through a cycle of four chemical reactions. In the first step, detritylation, the dimethoxytrityl (DMT) group is removed with trichloroacetic acid to free the 5' hydroxyl for the coupling reaction. The second step is coupling, in which the 5'-OH of the nucleotide reacts with an activated monomer created by simultaneously adding the phosphoramidite nucleoside monomer and tetrazole. The tetrazole protonates the nitrogen of the phosphoramidite, making it susceptible to nucleophilic attack. The third step, capping, terminates any chains that did not undergo coupling. Unreacted chains have a free 5'-OH and are capped by acetylation with acetic anhydride and 1-methylimidazole. Capping minimizes the length of impurities, making it easy to do post-synthesis trityl-selective purification of the final product. Finally, the internucleotide linkage is converted from a phosphite to the more stable phosphotriester by oxidation. After oxidation the DMT group is removed with trichloroacetic acid and the cycle is repeated until the chain elongation is complete. The protected oligo is cleaved from the support with concentrated ammonium hydroxide and methylamine and is ready for post-synthesis deprotection and purification.
MerMade-192 Oligonucleotide SynthesizerUnicorn For Oligonucleotide Synthesis User Manual 18-1134-71 5
There are three main hardware components in the MerMade-192, the inner reaction chamber, the outer chamber, and the motion/injection system. The two 96-well plates are placed inside two separate vacuum chucks which are then placed into the inner chamber. This outer chamber is of sufficient size to accommodate the full motion of the X-Y table. The injection head is mounted on the top of the outer chamber lid. The X-Y table is controlled by the computer and moves the plates around under the injection head, positioning the wells to receive the reagents. The two chambers ensure the process takes place in a moisture-free and chemically-inert environment. During the course of synthesis, argon is continually introduced into the inner chamber and the small gap at the top of the chamber guarantees a constant flow of gas through the chamber.
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