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car • today at 4:13 AM • 2 replies • view on HN

The device used to make oligonucleotides is pretty much an inkjet printer, from there it's cleverly applied enzymes to assemble the full strand.

Usually the synthesis of oligonuclotides is done with phosphoramidite chemistry [0]. So tell us more about those enzymes to make DNA molecules from scratch.

[0] https://www.twistbioscience.com/blog/science/simple-guide-ph...


Replies

mbreese • today at 5:04 AM

I’m pretty sure they were talking about how you can combine synthesized oligos into longer fragments when you are starting with smaller oligos. I’m guessing that they were referring to using different restriction enzymes from that point on.

Unless we are talking about really long oligos (which is harder and $$$), you’ll need some post-synthesis enzymatic work to get your full strand.

➕ show 1 reply
amirhirsch • today at 5:33 AM

Ansa Bio uses an engineered terminal deoxynucleotidyl transferase (TdT) enzyme to synthesize the oligos themselves, rather than using phosphoramidite chemistry. Each enzyme is tethered to a single nucleotide, allowing it to extend the DNA strand by exactly one base. The tether is then cleaved and the cycle repeats.

This works in aqueous solution under mild conditions and enables synthesis of much longer oligos (~1,000 bases), which can subsequently be assembled into 50 kbp constructs.

Not sure about that inkjet printer analogy.