基因,蛋白,免疫 课程之蛋白组学 1.doc

Lecture about protein protein interaction Example that we shall use is the interaction between an antibody and its antigen Antibodies are a brilliant example of adaptation in biological systems. The interaction between antigens and antibodies is exploited in our study of individual proteins. Learning objectives: By the end of your revision, you should understand the interactive forces that are responsible for stabilising the interactions that occur during biological processes. You should know why and how proteins are folded into simple secondary structures. Be familiar with the structure of antibodies and how the antigen binding site is generated. Understand the salient features that account for the interaction between lysozyme and the binding site of an antibody raised against it. Background reading: Introduction to Protein Structure By Carl Branden John Tooze Chapter 15 Standard Biochemistry text book Eg. Biochemistry By Reginald H. Garrett Charles M Grisham Chapters 2 5  Interactive forces involved Covalent bonds Hold atoms together ( molecules H, O, C and N are able to form covalent bonds by electron-pair sharing. Lightest elements capable of forming these bonds. H, O, C and N form the strongest covalent bonds Two other covalent bond forming elements; phosphorus and sulphur Weak chemical forces Form intramolecular and intermolecular interactions between atoms: Weak chemical Forces Van der Waals forces Hydrogen bonds Strength between Ionic bonds 4 – 30 kJ/mol Hydrophobic interactions Not strong enough to bind free atoms together But their cumulative number can impart stability by collective action is sufficient to impart stability to biological macromolecules Because the interactions that occur during biomolecular recognition are sufficiently weak, they are readily reversible under physiological conditions.  Van der Waals Attractive Forces Result of induced electrical interactions between closely approaching atoms or molecules as their neg