Daily Starter Explain how a peptide bond is formed. (What is the reaction called and how does it happen?)
TAKE OUT YOUR AMINO ACID CHART
Protein Structure The structure of a protein is very complex, with many twists and folds. Proteins are folded into a 3-dimensional structure and held together by chemical bonds.
4 Levels of Protein Structure Primary Secondary Tertiary Quaternary
Primary Structure (1 st Level) The linkage of amino acids in a specific order. This connection is made by dehydration condensation and called a peptide bond.
Disulfide Bridges Some primary structures include disulfide bridges These are formed when 2 cysteine amino acid molecules lost their H (hydrogen) and covalently bond together
DiSulfide Bridge (Primary structure)
Secondary Structure (2 nd Level) The polypeptide chain (chain of a.a.) will begin to form H-bonds with adjacent a.a. molecules H-bonds are somewhat weak so they will form, break, and reform as the protein continues to twist and take a shape.
Secondary Structure (2 nd Level) Many H-bonds are needed to hold together a secondary structure (the more, the stronger the hold) There are 2 kinds of secondary folding patterns: 1.Alpha Helix 2.Beta pleated sheets
Alpha Helix The slightly negative Oxygen from the carboxyl (COO-) forms a H-bond with the slightly positive Hydrogen from the amino group (NH3+)
Beta Pleated Sheet The slightly negative Oxygen from the carboxyl (COO-) forms a H-bond with the slightly positive Hydrogen from the amino group (NH3+)
Video on Protein Folding