 The last part of mixed structures I want to show you are these. These are alpha plus beta proteins that contain their binding DNA. And it turns out in particular the beta sheets are going to be really useful here because the beta sheet will expose the hydrogen bonds that can interact with the bases. The first one, this is called a so-called sink finger protein. If you have lots of imagination you can think of this as a hand and then you're binding a sink here. I said that you needed lots of imagination. Try to look it up online and I bet you're going to find a hand illustration somewhere. This other protein is called a Tata binding protein. It has nothing to do with the Indian consulting company Tata. This is a, do you see again that it's naturally twisting? That had to do with the propensity of beta sheets to twist. This twist has also evolved to fit perfectly in the major groove of DNA. So what do you think that the Tata binding protein does? T, A, T, A. Where have you seen those letters? That's right, DNA basis. So this particular protein binds the sequence Tata in DNA and it's a so-called transcription factor. So it's a protein that it somewhat diffuses almost along the DNA strand, binds to a particular part and helps initiate transcription. That is where we're going to start reading the genetic code that will enable us to build more proteins. And here you see the turnover. It's proteins themselves are responsible for the factors that build proteins. It's a protein deciding where we should start to read the DNA. It's a protein doing the reading of DNA. It's a protein doing the duplication of DNA. It's a protein splicing together basis into mRNA. It's a protein taking the mRNA and reading it binding in the tRNA, now I'm talking about the ribosome, to create the actual protein. So it's proteins everywhere. Apart from the nucleic acids and lipids that are special cases, if anything is doing something in a cell, your first bed should be protein. And that is in principle all the secondary structures we're going to need. Sorry, not the secondary structures, all the protein structures. We have pure beta-beta sheet globular proteins. We had pure alpha helical globular proteins. And then we had these mixtures that were either alternating or segregated regions. Now