University:
Liberty University
Course:
BIOM 500 | Introduction to Biomedical Sciences
Academic year:

2024
Views:

406

Pages:

7
Author:

Sheha A.

Protein Structure * Proteins are made up of one or more polypeptide chains/protein chains. * Proteins with single polypeptide chains are called monomeric proteins, while proteins with more than one polypeptide chain are called oligomeric proteins. * Each polypeptide chain is an oligomer of amino acids. * Example: hemoglobin, lactate dehydrogenase (have 4 polypeptide chains) * Proteins are chains of amino acids. * Proteins exist as a coiled or folded structure or a 3-dimensional confirmation which is biologically active. * Structural organization of proteins: 1. Primary protein 2. Secondary protein Chaperones: * Chaperones are special group of proteins that bind with unfolded proteins to assist the folding and help the proteins to fold into their stable conformations. Primary Structure * Primary structure of proteins indicates the number and sequence of amino acid residues from N-terminal to C-terminal. Features: * Peptide bonds form the backbone of primary structure. * Amino acids are arranged in linear chain. * The primary structure of each protein has a unique amino acid sequence. This sequence is determined by the genes contained in DNA. * Primary structure is not a random sequence. * The primary structure of protein (specific sequence of amino acids) determines the higher levels of protein's structure. * The biological activities of the protein are related to their 3-dimensional structures. These 3D structures depend on the primary sequence. * A slight change in the primary sequence of protein may result in the loss of biological activity of protein. * Eg: sickle cell anemia, a change in a single amino acid sequence results in the malformation of hemoglobin. * Secondary Structure * Twisting and folding of polypeptide chains result in secondary structure. * Secondary structures form the backbone of the tertiary structure.