BCHM 3050 1st Edition Lecture 9Outline of Last Lecture I. Tertiary Protein StructuresII. Quaternary Protein StructuresIII. Unstructured ProteinsIV. Protein foldingV. Anfinsen ExperimentsVI. DenaturationVII. Molecular ChaperonesVIII. Protein DegradationIX. Diseases Associated with Misfolded ProteinsOutline of Current Lecture I. Mad Cow PrionsII. Fibrous Proteins III. CollagenIV. Globular Proteins – Myoglobin vs. HemoglobinV. Oxygen Binding Equilibrium CurvesVI. Effects of pH on Oxygen BindingCurrent LectureI. Mad Cow PrionsThese 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.a. When consume undercooked meat, can consume these misfolded proteins and cause more misfoldingb. Pre-prions covert to prions, which can fold abnormallyc. A lot of unnecessary beta sheets in misfolded prionsII. Fibrous Proteins a. Fibrous protiens – main function is structural supportb. Enzymes are generally not fibrousc. Keratin is rich is alpha helices (KNOW THIS!)d. Silk fibroin (forms spider webs) is a fibrous protein rich in beta sheetse. Simple, do not usually form a tertiary/quaternary structureIII. Collagena. Collagen has left handed alpha helices that twist in a way that they assume an overall right handed conformationb. Glyines and prolines are usually not found in alpha helices, only in turns; but theyare found in these left handed alpha helices (abnormal case)c. Early on in the collagen life, lysine (basic amino acid) and lueine (nonpolar) are able to create crosslinks à support, flexibled. With age, the connections are lost and before softer à wrinklese. Skin age products try to work on how to prevent the loss of these crosslinksIV. Globular Proteins – Myoglobin vs. Hemoglobina. Same prosthetic groupi. Prosthetic group – like a co-factor; help protein to do its jobii. Iron is the core of the prosthetic group and the amino acid next to iron is histidineb. Very similar functionc. Myoglobin is a monomer; hemoglobin is a tetramerd. Blue blood = hemoglobin devoid of oxygene. Red blood = hemoglobin with oxygen; RBCs are rich in oxygenf. Hemophilia – anemia and hemoglobin is not able to retain oxygen, instead it is saturated in CO2g. Blood unloads oxygen in tissue, need myoglobin in tissues to accept oxygen and slowly release it over timeh. Hemoglobin more active in the lungsi. Myoglobin more active in the tissuesj. Both can accept oxygenk. hemoglobin’s lower affinity to oxygen enables it to release the oxygen to myoglobin in the tissuesl. Myoglobin only has one binding site for oxygenm. Hemoglobin has multiple oxygen binding sitesn. More binding sites = less affinityo. Less binding sites = more affinityV. Oxygen Binding Equilibrium Curvesa. Myoglobin – hyperbolic curve = stronger affinity for oxygenb. Hemoglobin – sigmoid curve = lower affinity for oxygenVI. Effects of pH on Oxygen Bindinga. Ex: workout a lot à pain in muscles à lactic acid accumulation due to depletion of oxygen à lowers pH à hemoglobin cannot get to oxygenb. Lower pH dissociates hemoglobin from
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