So now that we've introduced the Alfa Helix, let's talk about the Alfa Helix screw sense. So I'll see you guys in those practice videos He'll sees in this protein structure, and so we'll talk more about protein structure, um, Alfa jealousies and protein structure and our next videos, and we'll get a little bit of practice and then we'll continue our lessons. So again, over here, what you'll see is that we've got our hydrogen bonds that are stabilizing our alfa helix, and what you can also see is that these Alfa Healy sees they can come together in a protein structure so you can see that we've got to Alfa. But you can also see that sometimes you'll find Alfa Helix is depicted as cylinders, and we'll see that in some of our examples as well. So this is the way that Alfa Healy Cesaire normally depicted. And so over here on the left, what we have is our ribbon. And so Alfa Ulysses are normally depicted in a ribbon shape, but they can be also depicted in a cylinder shape and so you can see that down below in our example where we have these Alfa helix depictions. He's in different ways, and so it's important to be able to recognize these different depictions. And so your textbook and your professor might actually depict these Alfa. And so again, these hydrogen bonds are parallel to the axis of the Alfa helix. Alfa Helix is so it's important to keep that in mind for Alfa Hillis is because when we get to beta sheets, that's going to be one of the distinguishing features, the direction of these hydrogen bonds. You'll see that these lines thes hydrogen bonds are almost parallel, and you don't really see any hydrogen bonds that air perpendicular and go across sideways. They're pretty much almost parallel to the axis of the helix, which again, if I had, like, the axis of the Helix, it'll be down the center. And the hydrogen bonds, which are stabilizing the Alfa Helix here are in yellow, highlighted here and notice that thes yellow hydrogen bonds, which I'll mark and read here. And so if we take a look at our example down below, which will see is that this helix here has an axis in the axis of the helix is pretty much going in this direction here. They're nearly parallel to the axis of the Alfa Helix. And so what you'll notice is that the backbone, hydrogen bonds are actually nearly parallel. It's all the backbone hydrogen bonds, and so the hydrogen bonds in the backbone can actually formed between distant amino acid residues on the same chain.

So the our group is not involved in stabilizing the Alfa helix. Very particular hydrogen bonds thes air hydrogen bonds that form in the backbone of the Alfa Helix. But it's not any hydrogen bonds thes air. And so, really, the spiral, like coiled confirmation of the Alfa helix is stabilized by hydrogen bonds. So you can see down here in our image this coiled confirmation that our backbone takes on. And it has a coiled, periodic spiral like confirmation, like the ones that you've seen and you're already familiar with from your previous courses. And really, this is a type of secondary structure where the protein backbone takes on a coiled confirmation. So the Alfa Helix is again a type of secondary protein structure. So now that we've talked about peptide bonds, primary protein structure and Rama Condron plots, which remember can reveal secondary structures, let's talk about some of those secondary structures, and we're going to start off by talking about the Alfa Helix.

Peptide backbone of alpha helix