12The hydrolysis and condensation of peptide bonds.
13The sequence of amino acids along The peptide chain is called thePrimary structure.The secondary structure of the peptide chainIs the natural shape of the chainCaused by the tetrahedral chemical bonds.
14One form of the secondary structure of the peptide chain Is called -helix.
15the structure of the -helical polypeptide chain.
16Another form of the secondary structure is called the -pleated sheet.
17Another form of the secondary structure, the -pleated sheet.
18The tertiary structure of the polypeptide chain Describes the bending and folding of theHelical structure.Electrostatic attractive force (ionic bond),Covalent bond, disulphide bond,And the Van der Waal force contributeTo these foldings.
19Formation of the disulphide linkage between 2 sulphur containing amino acids.
20Hydrogen bonds within the polypeptide chain would holding the bending of the amino acid backbone.Disulphide bondDisulphide bond is a covalent bond, which hold the foldingof the amino acid backbone permanently.
21The maintenance of the tertiary structure of the protein.
22The peptide chains can be inter-linked with cross-bridges, the disulphide bonds.
25The quaternary structure describes the association among the polypeptide chains and the non-proteinous groups.
26The conformation of the protein is very important. If the conformation is changed, the property ofthe protein will also be changed.
27For example,if the the haemagglutinine of the current H5N1 virushas one amino acid changed,its conformation would be changed.The conformation may become much easierto combine with the receptor protein on thesurface of the human cells.Then, human would become susceptible to theinfection of the virus.