Podcast
Questions and Answers
What is the term used to describe the reversible binding of other molecules by proteins?
What is the term used to describe the reversible binding of other molecules by proteins?
What characteristic of a binding site allows a protein to selectively bind only one or a few types of molecules?
What characteristic of a binding site allows a protein to selectively bind only one or a few types of molecules?
What is the term for the molecule bound reversibly by a protein?
What is the term for the molecule bound reversibly by a protein?
What allows an organism to respond rapidly and reversibly to changing environmental and metabolic circumstances?
What allows an organism to respond rapidly and reversibly to changing environmental and metabolic circumstances?
Signup and view all the answers
What does a ligand bind to on a protein?
What does a ligand bind to on a protein?
Signup and view all the answers
What is the term used to describe a protein's ability to discriminate among the thousands of different molecules in its environment and selectively bind only one or a few types?
What is the term used to describe a protein's ability to discriminate among the thousands of different molecules in its environment and selectively bind only one or a few types?
Signup and view all the answers
What is the major class of antibodies?
What is the major class of antibodies?
Signup and view all the answers
Which antibody preparation is produced by many different B lymphocytes responding to one antigen?
Which antibody preparation is produced by many different B lymphocytes responding to one antigen?
Signup and view all the answers
What is the molecular weight of Myosin?
What is the molecular weight of Myosin?
Signup and view all the answers
Which protein binds to the thin filament and blocks the myosin-binding sites?
Which protein binds to the thin filament and blocks the myosin-binding sites?
Signup and view all the answers
What causes a conformational change in a troponin-tropomyosin complex and exposes myosin-binding sites?
What causes a conformational change in a troponin-tropomyosin complex and exposes myosin-binding sites?
Signup and view all the answers
What is the basis for a variety of important analytical procedures?
What is the basis for a variety of important analytical procedures?
Signup and view all the answers
Which of the following is true about the Bohr effect?
Which of the following is true about the Bohr effect?
Signup and view all the answers
What is the function of 2,3-bisphosphoglycerate (BPG) in hemoglobin?
What is the function of 2,3-bisphosphoglycerate (BPG) in hemoglobin?
Signup and view all the answers
What is the primary difference between fetal hemoglobin and normal adult hemoglobin?
What is the primary difference between fetal hemoglobin and normal adult hemoglobin?
Signup and view all the answers
In the immune system, what is the role of cytotoxic T cells (TC cells)?
In the immune system, what is the role of cytotoxic T cells (TC cells)?
Signup and view all the answers
What is the purpose of a vaccine in the immune system?
What is the purpose of a vaccine in the immune system?
Signup and view all the answers
What is an antigen?
What is an antigen?
Signup and view all the answers
What is the primary reason for myoglobin's distal His enhancing heme's O2 affinity?
What is the primary reason for myoglobin's distal His enhancing heme's O2 affinity?
Signup and view all the answers
What prevents CO poisoning from metabolism and industrial sources?
What prevents CO poisoning from metabolism and industrial sources?
Signup and view all the answers
What is the primary function of erythrocytes in relation to hemoglobin?
What is the primary function of erythrocytes in relation to hemoglobin?
Signup and view all the answers
What stabilizes hemoglobin's quaternary structure?
What stabilizes hemoglobin's quaternary structure?
Signup and view all the answers
What triggers a conformational change in hemoglobin from T to R state?
What triggers a conformational change in hemoglobin from T to R state?
Signup and view all the answers
What influences the hybrid sigmoid binding curve of hemoglobin?
What influences the hybrid sigmoid binding curve of hemoglobin?
Signup and view all the answers
Which type of protein shows conformational changes in one subunit affecting others?
Which type of protein shows conformational changes in one subunit affecting others?
Signup and view all the answers
What is the coordination number of iron in heme?
What is the coordination number of iron in heme?
Signup and view all the answers
Which type of iron in heme binds O2 reversibly?
Which type of iron in heme binds O2 reversibly?
Signup and view all the answers
What does the dissociation constant (Kd) measure?
What does the dissociation constant (Kd) measure?
Signup and view all the answers
Which ligand binds free heme much better than O2?
Which ligand binds free heme much better than O2?
Signup and view all the answers
What affects the binding geometries of carbon monoxide (CO) and O2 to heme?
What affects the binding geometries of carbon monoxide (CO) and O2 to heme?
Signup and view all the answers
What is the term used to describe the reversible binding of other molecules by proteins?
What is the term used to describe the reversible binding of other molecules by proteins?
Signup and view all the answers
What allows an organism to respond rapidly and reversibly to changing environmental and metabolic circumstances?
What allows an organism to respond rapidly and reversibly to changing environmental and metabolic circumstances?
Signup and view all the answers
What is the term for the molecule bound reversibly by a protein?
What is the term for the molecule bound reversibly by a protein?
Signup and view all the answers
What is the primary function of erythrocytes in relation to hemoglobin?
What is the primary function of erythrocytes in relation to hemoglobin?
Signup and view all the answers
What is the term used to describe a protein's ability to discriminate among the thousands of different molecules in its environment and selectively bind only one or a few types?
What is the term used to describe a protein's ability to discriminate among the thousands of different molecules in its environment and selectively bind only one or a few types?
Signup and view all the answers
What influences the hybrid sigmoid binding curve of hemoglobin?
What influences the hybrid sigmoid binding curve of hemoglobin?
Signup and view all the answers
What is the coordination number of iron in heme?
What is the coordination number of iron in heme?
Signup and view all the answers
What is the primary reason for myoglobin's distal His enhancing heme's O2 affinity?
What is the primary reason for myoglobin's distal His enhancing heme's O2 affinity?
Signup and view all the answers
What does the dissociation constant ($K_d$) measure?
What does the dissociation constant ($K_d$) measure?
Signup and view all the answers
What allows an organism to respond rapidly and reversibly to changing environmental and metabolic circumstances?
What allows an organism to respond rapidly and reversibly to changing environmental and metabolic circumstances?
Signup and view all the answers
What is the term used to describe the reversible binding of other molecules by proteins?
What is the term used to describe the reversible binding of other molecules by proteins?
Signup and view all the answers
What is the basis for a variety of important analytical procedures?
What is the basis for a variety of important analytical procedures?
Signup and view all the answers
What is the coordination number of iron in heme?
What is the coordination number of iron in heme?
Signup and view all the answers
What is the primary function of erythrocytes in relation to hemoglobin?
What is the primary function of erythrocytes in relation to hemoglobin?
Signup and view all the answers
What causes a conformational change in a troponin-tropomyosin complex and exposes myosin-binding sites?
What causes a conformational change in a troponin-tropomyosin complex and exposes myosin-binding sites?
Signup and view all the answers
What is the major class of antibodies?
What is the major class of antibodies?
Signup and view all the answers
What is the molecular weight of Myosin?
What is the molecular weight of Myosin?
Signup and view all the answers
What is the basis for a variety of important analytical procedures?
What is the basis for a variety of important analytical procedures?
Signup and view all the answers
What is the primary function of erythrocytes in relation to hemoglobin?
What is the primary function of erythrocytes in relation to hemoglobin?
Signup and view all the answers
What influences the hybrid sigmoid binding curve of hemoglobin?
What influences the hybrid sigmoid binding curve of hemoglobin?
Signup and view all the answers
What is the primary difference between fetal hemoglobin and normal adult hemoglobin?
What is the primary difference between fetal hemoglobin and normal adult hemoglobin?
Signup and view all the answers
What prevents CO poisoning from metabolism and industrial sources?
What prevents CO poisoning from metabolism and industrial sources?
Signup and view all the answers
What is the function of 2,3-bisphosphoglycerate (BPG) in hemoglobin?
What is the function of 2,3-bisphosphoglycerate (BPG) in hemoglobin?
Signup and view all the answers
What stabilizes hemoglobin's quaternary structure?
What stabilizes hemoglobin's quaternary structure?
Signup and view all the answers
What is the primary function of 2,3-bisphosphoglycerate (BPG) in hemoglobin?
What is the primary function of 2,3-bisphosphoglycerate (BPG) in hemoglobin?
Signup and view all the answers
What is the primary role of fetal hemoglobin?
What is the primary role of fetal hemoglobin?
Signup and view all the answers
What is the primary function of the humoral immune system?
What is the primary function of the humoral immune system?
Signup and view all the answers
What is the primary role of T lymphocytes in the cellular immune response?
What is the primary role of T lymphocytes in the cellular immune response?
Signup and view all the answers
What is the primary function of a vaccine in the immune system?
What is the primary function of a vaccine in the immune system?
Signup and view all the answers
What is the primary characteristic of haptens in the context of immune response?
What is the primary characteristic of haptens in the context of immune response?
Signup and view all the answers
Study Notes
Principles of Protein Function and Reversible Interactions
- Protein-ligand binding involves conformational changes in the protein structure, with induced fit being a specific adaptation.
- Multisubunit proteins show conformational changes in one subunit affecting others, and interactions between ligands and proteins may be regulated.
- Myoglobin and hemoglobin are extensively studied oxygen-binding proteins, crucial for the evolution of oxygen transport in multicellular organisms.
- Heme is a protein-bound prosthetic group consisting of a complex organic ring structure with a bound Fe2+ atom, preventing the formation of reactive oxygen species.
- Iron in heme forms six coordination bonds, with Fe2+ binding O2 reversibly, while Fe3+ does not.
- The globin family of proteins, including myoglobin, hemoglobin, neuroglobin, and cytoglobin, have a highly conserved tertiary structure and different functions in O2 transport or storage.
- Myoglobin has a single binding site for oxygen, with the majority of its amino acid residues found in the eight α helices typical of the globin fold.
- The reversible binding of a protein to a ligand can be quantitatively described using an equilibrium expression and association constant (ka) to measure ligand affinity.
- The dissociation constant (kd) is the equilibrium constant for the release of ligand, with lower Kd indicating higher affinity.
- Protein structure affects how ligands bind, with carbon monoxide (CO) binding free heme much better than O2, but the difference in relative affinity is mediated by the globin structure.
- Oxygen binds to heme with the O2 axis at an angle, readily accommodated by myoglobin, while carbon monoxide binds to free heme with the CO axis perpendicular to the porphyrin ring.
- Differences in the orbital structures of CO and O2 affect their binding geometries, highlighting the importance of protein structure in ligand binding.
Hemoglobin: Structure, Function, and Regulation
- Myoglobin's distal His enhances heme's O2 affinity via hydrogen bonding, stabilizing the Fe-O2 complex 20,000-fold stronger than free heme for CO compared to O2
- This selective O2 affinity enhancement in globins prevents CO poisoning from metabolism and industrial sources
- Hemoglobin is formed from hemocytoblasts, loses organelles in maturation, and survives for about 120 days in humans
- Erythrocytes transport O2, carrying high concentrations of hemoglobin; arterial blood is ~96% saturated with O2, releasing about one-third of oxygen per 100 mL passing through tissue
- Hemoglobin has two globin types (α and β chains), undergoes conformational changes for O2 binding and release
- Strong interactions between unlike subunits, hydrophobic effects, hydrogen bonds, and ion pairs stabilize hemoglobin's quaternary structure
- Hemoglobin has R and T states, with T state stabilized by ion pairs at the α1β2 interface
- O2 binding to hemoglobin triggers a conformational change from T to R state, affecting ion pairs and conformation near heme
- Hemoglobin binds O2 cooperatively, with a hybrid sigmoid binding curve, influenced by pO2 levels in lungs and tissues
- Hemoglobin is an allosteric protein, binding O2 and modulating its conformation
- Hemoglobin transports H+ and CO2, influenced by pH and CO2 concentration, and carries them to the lungs and kidneys for excretion
- Carbonic anhydrase in RBCs catalyzes the hydration of CO2 to bicarbonate, influencing oxygen binding and release in the blood
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Test your knowledge of protein function and reversible interactions with this quiz. Explore topics such as protein-ligand binding, myoglobin and hemoglobin, heme structure, ligand affinity, and the influence of protein structure on ligand binding.
