11 thoughts on “S6 – Sherlock

  1. Are there other bacterium that can also insert their DNA into these soybean species? Or is this the only one?

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    1. This is the only one I know of, but I bet that there is a family of similar species which do the same kind of thing. The reason why the bacterium is able to insert a plasmid into the soybean cell is that in its normal lifecycle, it inserts a ‘tumor inducing’ plasmid into a plant. It does this because the tumor created is an especially nice place for the bacteria to grow and divide.

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  2. Did you change anything in your methods when you performed another selection to obtain the proper DNA sequence?

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    1. No, we were only one base off so it seemed like our methods were working well. Because of the low error rate in bacterial replication (1 in 10^9 mutations per base pair), the error was probably in the original synthetic sequence we ordered.

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  3. Do you know what proteins you would look for on a Western blot test in the future to make sure collagen is expressing?

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    1. A properly folded collagen triple helix is very high weight (the collagen polypeptide is very long), so we would probably just look for the collagen itself by weight.

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  4. What exactly is Golden Gate assembly? Is it possible to give a very general simplification or is the process too complex?

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    1. It is kind of hard to explain without a diagram, but the main idea is similar to how you would make recombinant DNA with type-1 restriction enzymes (the kind that you work with in phage lab), if you know about that. If you don’t know, the sticky ends generated by the restriction enzyme are the same, so if you have many pieces of DNA cut by the same restriction enzyme and put them in solution, they can anneal with other pieces randomly based on the complementary sequence of the sticky end. If you introduce ligase to that reaction, these new recombinant DNA molecules can be connected together permanently.

      The difference in Golden Gate assembly is that you use type 2 restriction enzymes, which are the same except that they make their cut a few base pairs away from their recognition site, so that you can design the sticky end to be whatever you want. It also means that you can make it so the recognition sites for the restriction enzyme are not in the final product. This is where you would want a diagram to explain things – but you can imagine that if your insert has the recognition sites on the outside, and your plasmid has the recognition sites on the inside, when the insert goes into the plasmid there will no longer be any recognition sites. This gives you an essentially one-way reaction which only generates the product you want.

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  5. What exactly is Golden Gate assembly? Is it possible to give a very brief overview of this technique or is the process too complex?

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    1. There are certainly many organisms which could be good producers of synthetic human collagen (bacteria, yeast, plants, even animals). I think that the reason we chose soybeans in the first place was that plants generally seemed underutilized in synthetic biology, and soybeans are good growers.

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