Friday, May 29, 2009

What's going on at the lab?

My protein synthesis functions, got me thinking about developing an animated model of protein synthesis that actually does transcription and translation and so I have been trying to figure out a good way to do this. The figure shows a animated prototype for an operon that I have been working on. The model loosely mimics the behavior of the repressor protein and inducer of the lac operon as well as the RNA polymerase.

In the picture the repressor protein (red) is sitting on the operator and the RNA polymerase(purple) cannot attach to the promoter to begin transcription of the operon's coding region (teal). The inducer is the green ball. The can see how the system behaves by touching say the inducer which will then bind to the repressor protein, preventing it from blocking the RNA polymerase.

This view shows the repressor protein not on the operator allowing the RNA polymerase to begin transcription. As the polymerase moves down the coding region the transcript (yellow) grows.

When the RNA polymerase reaches the terminator part of the operon the polymerase detaches, the RNA detaches and the small ribosomal subunit (brown) attaches to the start of the start of the transcript.

Obviously there are some simplifications here. For instance in prokaryotes translation can begin while transcription is still on going and I don't bother with the details of how RNA polymerase works.

The goal is to let the students input a short DNA sequence, animate transcription and show the mRNA in local chat (or perhaps as hovering text above the mRNA) and optionally send it as an e-mail. Then as translation proceeds actually have the tRNA's bring in the amino acids and make a short polypeptide. In this scheme the mRNA is a single prim but carries the codons as data inside. But the development of the polypeptide via translation is explicitly animated in terms of what happens at the ribosome, each amino acid shown as a separate object.

In the foreground are some crude tRNA's (orange rectangles) some of which have amino acids represented by balls attached to them. This is going to be a fairly elaborate scripting effort with some neat tricks involved so stay tuned...

My sabbatical is officially over and have already given my sabbatical report. I will be teaching summer school-just two intro biology lecture sections. Also at the end of July I will be speaking on Science simulations in Second Life at SidLit and giving also giving several local talks about Second Life in general.

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