Podcast
Questions and Answers
What term describes complexes that have reciprocating mechanisms?
What term describes complexes that have reciprocating mechanisms?
Which type of asymmetry is rarely observed among identical subunits?
Which type of asymmetry is rarely observed among identical subunits?
What is the concept where all subunits cycle through the same set of conformations?
What is the concept where all subunits cycle through the same set of conformations?
Which form of symmetry involves asymmetric structures that are similar but differing in conformation?
Which form of symmetry involves asymmetric structures that are similar but differing in conformation?
Signup and view all the answers
What does pseudosymmetry imply about the symmetry of a complex?
What does pseudosymmetry imply about the symmetry of a complex?
Signup and view all the answers
What is the arrangement of the subunits in the enzyme aspartate transcarbamoylase?
What is the arrangement of the subunits in the enzyme aspartate transcarbamoylase?
Signup and view all the answers
What symmetry group does the homohexamer of aspartate transcarbamoylase belong to?
What symmetry group does the homohexamer of aspartate transcarbamoylase belong to?
Signup and view all the answers
Which of the following statements is true about the structural representation of D3 symmetry?
Which of the following statements is true about the structural representation of D3 symmetry?
Signup and view all the answers
Which type of symmetry do both the Norwalk virus capsid and mammalian ferritin display?
Which type of symmetry do both the Norwalk virus capsid and mammalian ferritin display?
Signup and view all the answers
What is the primary function of the DNA polymerase delta processivity factor?
What is the primary function of the DNA polymerase delta processivity factor?
Signup and view all the answers
How many subunits make up the mammalian ferritin structure?
How many subunits make up the mammalian ferritin structure?
Signup and view all the answers
What is the significance of the hollow core in the structure of ferritin?
What is the significance of the hollow core in the structure of ferritin?
Signup and view all the answers
What would you use to view the 3D structures of the proteins mentioned?
What would you use to view the 3D structures of the proteins mentioned?
Signup and view all the answers
What type of interactions stabilize quaternary structures of proteins?
What type of interactions stabilize quaternary structures of proteins?
Signup and view all the answers
Which of the following describes a structure with C3 symmetry?
Which of the following describes a structure with C3 symmetry?
Signup and view all the answers
Which type of oligomer is characterized by having a defined limit to the number of subunits present?
Which type of oligomer is characterized by having a defined limit to the number of subunits present?
Signup and view all the answers
What does the hydrophobic effect contribute to in protein quaternary structures?
What does the hydrophobic effect contribute to in protein quaternary structures?
Signup and view all the answers
What is true about dihedral groups in protein oligomers?
What is true about dihedral groups in protein oligomers?
Signup and view all the answers
Which of the following is an example of a closed quaternary structure?
Which of the following is an example of a closed quaternary structure?
Signup and view all the answers
How many half turns does an oligomer with C2 symmetry take to reorient itself to the same view?
How many half turns does an oligomer with C2 symmetry take to reorient itself to the same view?
Signup and view all the answers
Which of the following statements about oligomers with cyclic symmetry is correct?
Which of the following statements about oligomers with cyclic symmetry is correct?
Signup and view all the answers
What aspect of biology is primarily addressed in the source content?
What aspect of biology is primarily addressed in the source content?
Signup and view all the answers
Which type of publication is the source content taken from?
Which type of publication is the source content taken from?
Signup and view all the answers
What is the primary focus of the article's authors?
What is the primary focus of the article's authors?
Signup and view all the answers
What type of symmetry is likely discussed concerning proteins based on the title?
What type of symmetry is likely discussed concerning proteins based on the title?
Signup and view all the answers
When was the publication issued?
When was the publication issued?
Signup and view all the answers
Which two fields are combined in the publication's subject matter?
Which two fields are combined in the publication's subject matter?
Signup and view all the answers
The content's title suggests that it addresses the interplay between which two concepts?
The content's title suggests that it addresses the interplay between which two concepts?
Signup and view all the answers
Who are the authors of the publication?
Who are the authors of the publication?
Signup and view all the answers
What characteristic makes large proteins more stable against denaturation compared to smaller proteins?
What characteristic makes large proteins more stable against denaturation compared to smaller proteins?
Signup and view all the answers
Which of the following statements about large oligomeric proteins is true?
Which of the following statements about large oligomeric proteins is true?
Signup and view all the answers
Which type of proteins are less likely to denature due to their structural complexity?
Which type of proteins are less likely to denature due to their structural complexity?
Signup and view all the answers
In terms of stability against denaturation, how do large soluble proteins compare to membrane-bound proteins?
In terms of stability against denaturation, how do large soluble proteins compare to membrane-bound proteins?
Signup and view all the answers
What role do subunits play in the structure of large oligomeric proteins?
What role do subunits play in the structure of large oligomeric proteins?
Signup and view all the answers
How does the construction of large proteins generally affect their behavior in solvents?
How does the construction of large proteins generally affect their behavior in solvents?
Signup and view all the answers
What does the evolution of oligomeric complexes often favor?
What does the evolution of oligomeric complexes often favor?
Signup and view all the answers
Which characteristic is NOT typical of large proteins?
Which characteristic is NOT typical of large proteins?
Signup and view all the answers
Which of the following statements about global asymmetry in complexes is true?
Which of the following statements about global asymmetry in complexes is true?
Signup and view all the answers
What is the primary reason that large symmetrical proteins are constructed in a specific way?
What is the primary reason that large symmetrical proteins are constructed in a specific way?
Signup and view all the answers
What drives local asymmetry at the level of side chain conformation?
What drives local asymmetry at the level of side chain conformation?
Signup and view all the answers
How do subunits behave over time in asymmetric complexes?
How do subunits behave over time in asymmetric complexes?
Signup and view all the answers
Which of the following best depicts the relationship between symmetry and the evolution of oligomeric complexes?
Which of the following best depicts the relationship between symmetry and the evolution of oligomeric complexes?
Signup and view all the answers
What characterizes nearly all crystallographic point groups?
What characterizes nearly all crystallographic point groups?
Signup and view all the answers
Which aspect is rarely observed in the study of complex symmetry?
Which aspect is rarely observed in the study of complex symmetry?
Signup and view all the answers
In the context of side chain conformation, what can drive functional local asymmetry?
In the context of side chain conformation, what can drive functional local asymmetry?
Signup and view all the answers
Study Notes
Quaternary Structure
- Quaternary structure is the association of two or more protein chains to form a larger protein complex.
- If the chains are identical, the protein is a homo-oligomer.
- If the chains are different, the protein is a hetero-oligomer.
- Examples include dimers, trimers, tetramers, hexamers, and octamers.
- These structures have defined limits to the number of subunits present.
Oligomeric Protein Types
- Cyclic groups (Cn): Have one axis of symmetry (e.g., C2, C3).
- Dihedral groups (Dn): Have one Cn axis and n C2 axes of symmetry perpendicular to the Cn axis (e.g., D3).
Stability of Quaternary Structures
- Quaternary structure is stabilized by the same interactions that drive protein folding, including covalent and noncovalent interactions.
- Hydrophobic effect contributes to oligomer formation.
- The association of subunits reduces surface area to volume ratio. (e.g., in alkaline phosphatase, dimer stability to higher temperatures)
Protein Function
- Some proteins have machine-like properties (e.g., DNA polymerase delta processivity factor).
- Some proteins serve as containers (e.g., Norwalk virus capsid, ferritin).
- Heterooligomeric proteins (e.g., ATP synthase) are common, with multiple different subunits.
- Open oligomers can extend indefinitely (e.g., tubulin chains).
Genetic Economy and Efficiency
- Large proteins with multiple functions can be built from smaller, repeating units rather than one large protein. This reduces gene complexity and error rate, and increases stability and cooperativity.
Cooperativity
- Examples of cooperativity exist in Hemoglobin.
- O2 binding to one site causes conformation changes affecting other binding sites (increasing their oxygen affinity).
- Improves oxygen uptake and release in lungs and tissues.
Additional Information
- References are available for "Getting started with Structural Symmetry and Protein Function" and "Structural Symmetry & Protein Function" by Goodsell & Olson.
- Various structural files can be viewed in PyMOL.
- There are examples such as a movie of ferritin showing its differing perspectives, and a D3 symmetry movie.
- A review article by Goodsell and Olson, as well as related .pdf files and .pse (PyMOL) files, are recommended for further study. This is part of a larger review, you are requested to only read certain section from it.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Explore the intricacies of quaternary protein structures, focusing on their formation, types, and stability. This quiz delves into the concepts of homo-oligomers, hetero-oligomers, and factors affecting the stability of these complex proteins. Test your knowledge on the classifications and interactions that drive oligomer formation.
