BMS100 Assignment 1: Proteins PDF

BMS100 – Assignment 1: Proteins Please post your group’s completed assignment to Moodle in the Week 3 assignment drop-box. Please ensure all students names are included on the assignment. Only 1 person from each group needs to post the assignment. Warm-up questions: 1. Polyaspartate forms alpha heli...

BMS100 – Assignment 1: Proteins Please post your group’s completed assignment to Moodle in the Week 3 assignment drop-box. Please ensure all students names are included on the assignment. Only 1 person from each group needs to post the assignment. Warm-up questions: 1. Polyaspartate forms alpha helices in aqueous solutions below pH 3. a) What level of protein structure is an alpha helix? (1pt) b) Above a pH 5 it takes on a random coil configuration, please explain this observation. (pKR of Asp = 3.96) 2. The following amino acid substitutions within a protein have little effect on the protein’s function. Please explain why this is the case. a) Lysine to arginine b) Isoleucine to Leucine 3. Clinical Case: The red blood cell is flexible, disk-shape cell filled with up to 250 million molecules of hemoglobin. The red blood cell functions to deliver oxygen to body tissues, each hemoglobin protein can carry up to 4 oxygen molecules. To make room for all the hemoglobin, red blood cells do not contain a nucleus. Sickle cell anemia is an inherited disorder resulting in an anemia that causes fragile, breakable red blood cells that are deformed and tend to get stuck in smaller vessels. They can block these vessels causing pain and organ damage due to lack of oxygenation. Over time, they can damage the spleen, kidneys, brain, bones, and other organs. Hemoglobin is a dynamic protein; it can change its shape depending on whether or not it is bound to oxygen. Normally in a sickle cell patient, the Image adapted from: https://upload.wikimedia.org/wikipedia/commons/8/86/Risk-Factors-for-Sickle-Cellhemoglobin is relatively functional until a sickle cell Anemia_%281%292.jpg crisis. However, anything that reduce the amount of oxygen in the blood (think: exercise, flying at high altitudes, illness) can trigger a sickle cell crisis. During a sickle cell crisis, low oxygenation levels cause the shape of hemoglobin to be altered irreversibly. As a result, the red-blood cells take on their characteristic sickled shape. This is accompanied by significant worsening of symptoms, including pain (due to occlusion of blood vessels), worsening anemia symptoms, fever, and shortness of breath. The cause of sickle cell anemia is the result of a substitution of glutamate (normal) for Valine (sickle cell) in the β hemoglobin subunit. This single amino acid substitution within the hemoglobin protein is the cause of the abnormal red blood cell shape. a) Why would the single amino acid substitution result in such a significant problem? In your answer, consider how the interactions between hemoglobin molecules might change due to the amino acid substitution. Please link this to the change in red blood cell shape due to a sickle cell crisis? b) After a sick cell crisis, why can the red blood cell not simply replace this irreversibly altered hemoglobin with relatively functional hemoglobin?