Oligonucleotides can be synthesized, one nucleotide at a time, by adding activated monomers to a growing chain. Place the steps of chemical DNA synthesis in the correct order.
The first step is : 3' end of growing oligonucleotide attached to solid support.
Then there is four steps:
A
B
C
D
Steps repeat until all residues are added
E
Oligonucleotide cleaved from solid support
The options are:
1. acid removes DMT protecting group from 5'OH of nucleoside in growing chain
2. activated nucleotide (nucleoside phosphoramidite) adds, forming a 5',3. linkage
3. diisoprophylamio or other group activates the next nucleotide
4. protecting groups on bases and phosphates are removed
5. iodine oxidizes the 5',3' linkage yielding a phosphotriester.
Please tell me which steps go in A through E. I feel like I have tried every combo.
Based on the given information, let's try to determine the correct order of the steps for chemical DNA synthesis:
A - 3' end of growing oligonucleotide attached to solid support.
In this step, the solid support should be used to anchor the growing oligonucleotide's 3' end.
B - diisoprophylamio or other group activates the next nucleotide.
Here, a diisoprophylamio or another activating group should be used to activate the next nucleotide in order to prepare it for coupling.
C - activated nucleotide (nucleoside phosphoramidite) adds, forming a 5',3' linkage.
The activated nucleotide (nucleoside phosphoramidite) should be added in this step, forming a 5',3' linkage with the previously activated nucleotide.
D - acid removes DMT protecting group from 5'OH of nucleoside in growing chain.
To remove the DMT (dimethoxytrityl) protecting group from the 5'OH of the nucleoside in the growing chain, an acid should be used.
E - protecting groups on bases and phosphates are removed.
In the final step, the protecting groups on both the bases and phosphates need to be removed.
Steps repeat until all residues are added.
These steps should be repeated until all the desired nucleotide residues have been added.
Oligonucleotide cleaved from solid support.
Once the chemical synthesis is complete, the oligonucleotide should be cleaved from the solid support.
Based on this analysis, the correct order of the steps for chemical DNA synthesis is:
A - 3' end of growing oligonucleotide attached to solid support.
B - diisoprophylamio or other group activates the next nucleotide.
C - activated nucleotide (nucleoside phosphoramidite) adds, forming a 5',3' linkage.
D - acid removes DMT protecting group from 5'OH of nucleoside in growing chain.
E - protecting groups on bases and phosphates are removed.
Steps repeat until all residues are added.
Oligonucleotide cleaved from solid support.
Remember that each step may require specific reagents, temperature, and time to ensure successful DNA synthesis.