 Hi everyone welcome to the basic science series by Dr. Lokendra Kumar. I have created this program to promote scientific knowledge among students and young researchers. In the previous episode we discussed about the major histocompatibility complex in general. We also identified that there are three classes of major histocompatibility complex that is class 1, class 2 and class 3. In this presentation we will focus on the structure and function of major histocompatibility complex class 1 molecule in detail. We will also focus on the interaction of CD8 coreceptor and the function of various domains of MHC class 1 molecule. So please watch the full presentation to understand the structure and function of MHC class 1 molecule. The first question is where MHC class 1 molecules are found. They are present in almost all the cells of our body. They are present on the cell surface of all nucleated cells. It is very important to note down that they are present on platelets but not on the red blood cells. Let's know about the structure of MHC class 1 molecule. MHC class 1 molecules are heterodimers that means they are consist of two polypeptide chains alpha chain and beta 2 microglobulin chain. Alpha chain contains three domain alpha 1, alpha 2 and alpha 3. Alpha and beta microglobulin chains are linked non-covalently via interaction of beta 2 microglobulin and the alpha 3 domain. The alpha chain is encoded by a HLA gene while the beta 2 microglobulin unit is encoded by the beta 2 microglobulin gene. MHC class 1 molecule complex interacts with CD8 coreceptor and T cell receptor to recognize foreign molecules. The alpha 1 and alpha 2 domains fold to make up a groove for peptides to bind. It is very important to note down that the alpha 3 domain interacts with the CD8 coreceptor. The alpha 3-CD8 interaction holds the MHC1 molecule in place while the T cell receptor on the surface of cytotoxic T cells bind with the alpha 1, alpha 2 chains and checks the coupled peptide for its antigenicity. MHC class 1 molecule binds with peptides that are predominately 8 to 10 amino acid in length but the binding of longer peptides have also been reported. In the next episode, I will be covering exciting topics of immune systems so please stay tuned and don't forget to subscribe the YouTube channel. With this note, I conclude this presentation. I hope you understand what is MHC class 1 molecule and its role in human health. Please subscribe the channel and share the presentation with students and young researchers.