BCHM 30700 1st Edition Lecture 6 Outline of Last Lecture I Synthesis of Amino Acids II Essential Amino Acids A Definition of Essential Amino Acids B Definition of Nonessential Amino Acids III Amino Acids and Herbicides A Definition of ESPS Synthase IV Phosphorylation of Amino Acids V Acid and Base Review VI Amino Acid pKa Values Outline of Current Lecture I Formation of Peptides A Protein formation B Peptide bonds II Biological Peptides A Amino Acid Functions III Levels of Protein Structure IV Primary Structure A Definition of Amino Acid Composition B Definition of Amino Acid Sequence V Secondary Structure A Alpha Helices Current Lecture Amino acids can be joined together to form a chain called a peptide Peptides are normally under 100 amino acids long and also don t normally have structure to them A protein is formed through a long chain of peptides Proteins normally have around 100 1000 amino acids The linkage that connects amino acids together is known as a peptide bond The formation of the polar bond will cause water to be expelled in the process The bond will also eliminate the charge attached to the amine and carboxyl groups The polar bond formed allows for the formation of H bonds as well The peptide bond forms between the carboxyl group of one amino acid and the amino group of another This creates a sense of direction The amino end is called the N terminal and the carboxyl end is called the C terminal The peptide bones help to form the backbone of a protein These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute There are many examples of peptides within biology Insulin aspartame endorphins and other hormones are all peptides Oxytocin and Vasopressin are both hormones that participate in forming disulfide bridges due to have cysteines in their structures These sulfur bonds also help to make the peptide cyclic in shape Amino acids are involved in signaling such as through insulin They can be involved in movement such as with actin and myosin fibers Amino acids can have regulatory functions such as kinases Amino acids can also be involved in defense such as with antibodies There are 4 levels of structure that combine to form a protein The primary structure of the protein is what amino acids are in a given sequence The secondary structure is the 3 D one forms through peptide and H bonds that stabilize the protein The tertiary structure is forms through R group interactions within the various amino acids The quaternary structure is formed through proteins interacting with each other The primary structure is arguably the most important part of the protein The shape of the protein dictates its function The primary structure of amino acids are in a non random order Amino acid composition is what amino acids are present in the protein The Amino acid sequenceis what order a protein s amino acids are in This first layer of structure is what gives the protein its shape and therefore function What is within the primary structure dictates how all other parts of the protein will form A mutation in a single amino acid can have serious consequences The single change of glutamine to valine is what causes sickle cell anemia Changes in primary structure in general will decrease a proteins solubility A protein s secondary structure give the protein its three dimensional shape The secondary structure can be broken down into 4 groups alpha helix beta sheet turn and random coil An alpha helix structure is shaped like a spring The hydrogen bonding within peptides are what keeps the backbone stable In alpha helcies the R groups of the amino acids face outwards
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