Molecular Cell Biology Study Guide Exam 3
Molecular Cell Biology – Spring 2013
Study Guide – Exam #3
Protein Folding & Post-translational Modifications
-What are post-translational modifications? - are modifications that a proteins undergoes to achieve its mature state. Such as cutting, folding, splicing and other processes.
-How do proteins achieve their final conformation? - A protein achieves its final conformation by spontaneously folding. All the information that the protein needs as to how to fold is already located in the amino acid sequence of the protein.
-Why is conformation important? The two most important determinants of protein function are shape (conformation) and the cellular location. The protein MUST have the right shape and be localized in the right cellular location to be able to perform its job.
Folding:
-What’s the role of chaperons? - Help maintain the protein unfolded. Preventing incorrect folding and protein aggregation. Also allows the protein to achieve its correct conformation
-What do Chaperonins do? How is that different from what chaperons do? - Chaperons help maintain the protein in an open conformation, therefore preventing aggregation and misfolding. Chaperonins provide and “isolated” environment for proteings to fold in the absence of other interfering factors.
-What kind of physiological conditions trigger an upregulation in the synthesis of chaperons? A/Heat shock and other stress conditions. Hence their name “Heat Shock Proteins”. These proteins are thought to stabilize and facilitate the refolding of proteins that have been partially denatured as a result of exposure to elevate temperatures or other stress conditions.
-What’s the role of PDI (Protein Disulfide Isomerase)? How does it contribute to protein folding? Does it play a role in the folding of cytosolic proteins? Where is PDI located, i.e. in which cellular organelle? - Facilitates the formation of different disulfite bonds so that proteins can try
Study Guide – Exam #3
Protein Folding & Post-translational Modifications
-What are post-translational modifications? - are modifications that a proteins undergoes to achieve its mature state. Such as cutting, folding, splicing and other processes.
-How do proteins achieve their final conformation? - A protein achieves its final conformation by spontaneously folding. All the information that the protein needs as to how to fold is already located in the amino acid sequence of the protein.
-Why is conformation important? The two most important determinants of protein function are shape (conformation) and the cellular location. The protein MUST have the right shape and be localized in the right cellular location to be able to perform its job.
Folding:
-What’s the role of chaperons? - Help maintain the protein unfolded. Preventing incorrect folding and protein aggregation. Also allows the protein to achieve its correct conformation
-What do Chaperonins do? How is that different from what chaperons do? - Chaperons help maintain the protein in an open conformation, therefore preventing aggregation and misfolding. Chaperonins provide and “isolated” environment for proteings to fold in the absence of other interfering factors.
-What kind of physiological conditions trigger an upregulation in the synthesis of chaperons? A/Heat shock and other stress conditions. Hence their name “Heat Shock Proteins”. These proteins are thought to stabilize and facilitate the refolding of proteins that have been partially denatured as a result of exposure to elevate temperatures or other stress conditions.
-What’s the role of PDI (Protein Disulfide Isomerase)? How does it contribute to protein folding? Does it play a role in the folding of cytosolic proteins? Where is PDI located, i.e. in which cellular organelle? - Facilitates the formation of different disulfite bonds so that proteins can try