 We're going to need a ton of amino acids, too. Here are all of them, the 20 essential ones. Full names, three-letter abbreviations that are fairly obvious, but today with bioinformatics, we tend to run out of space. We use one-letter abbreviations for writing long sequences. Most of them are obvious, but then, for instance, arginine, I can't use A for that because that would be alanine, so I use arginine. Same asparagine that we use N for that. They're not entirely obvious, but if you are in this business, you tend to learn them by heart. The natural abundance is the frequency of amino acids that at this particular species. That, it determined not by physics, well, it is by physics, but it's the genetic code, not the solubility or any life process or anything. The more triplets that code for a particular amino acid, the larger its abundance in nature will be. And then, in the final column, we have the solubility in water. That we can determine with the methods that I showed you in previous lectures that we calculate delta G from the concentration. And here, you primarily see that the charged ones have gigantic negative numbers here, meaning that they're gonna love to be in water. But that means that it's gonna be very expensive to put them on the inside of a protein. You see histidine here, where we have two numbers. That's because of pH seven. Histidine can either be neutral and then it's relatively cheap to put it on the inside of a protein or it can be charged and then it would be very expensive to put it inside of the protein. The other amino acids that are worth knowing are these ones that are reasonably close to zero because they're gonna be somewhat happy either in water or on the inside of a protein. And that makes them very useful. I'll take you through a couple of them because it's instructive to look at what they mean and in particular how that relates to structure.