68 Questions
Integral membrane proteins Type I and Type II have the same domain orientation.
False
Kinases catalyze the reversible phosphorylation of specific serine, threonine, and tyrosine residues within other proteins.
True
Membrane-bound proteins play a role in modulation of enzymatic activity.
True
Most transmembrane helices have around 10-12 turns.
False
Types V and VI integral membrane proteins involve covalent lipid anchors.
True
Glycophorin is an erythrocyte glycoprotein where each hexagon represents a pentasaccharide.
False
Membrane bound proteins can only serve as receptors and cannot display enzymatic activity.?
False
Positive hydropathy windows for 20 residues in a row are indicative of a transmembrane domain?
True
A closer look at potassium transport is illustrated in PDB ID 1BL8?
False
Valinomycin's valine-like side chains prevent the complex from passing through the lipid bilayer?
False
The calcium pump of sarcoplasmic reticulum is a single polypeptide with a Mr ~100,000?
True
Aquaporin AQP-1 has a tetramer of different subunits, each subunit has one water permeable pore?
False
Slide 21 of 24 MPharm PHA111 Membrane Bound Proteins illustrates β-barrel membrane proteins?
True
Harder to get high quality structural information for membrane bound proteins than freely soluble ones?
True
The average hydropathy of 7-amino acid sequences is not taken and plotted in hydropathy plots?
False
Function not known, loss of sugars results in destruction of red blood cell?
True
Eight transmembrane α-helicies are present in a potassium channel from Streptomyces lividans?
True
The concentration gradient of K does not need to be maintained for the survival of microbial cells?
False
What is the primary function of kinases in biological signalling?
Catalyze the reversible phosphorylation of specific serine, threonine, and tyrosine residues within other proteins
What differentiates Type III integral membrane proteins from Type IV?
Presence of multiple transmembrane helices within a single polypeptide in Type III
What is the role of lipid anchors in membrane proteins?
Facilitate attachment to the membrane
What is the significance of the fluid mosaic model in membrane biology?
Describes the dynamic and heterogeneous nature of biological membranes
What happens as a result of reversible phosphorylation of specific residues by kinases?
Affects protein tertiary and quaternary structure, as well as protein-protein interactions
What is the primary role of membrane-bound proteins in biological systems?
Modulate enzymatic activity through protein-protein interactions
What is the main function of membrane-bound proteins?
Enzymatic activity and receptor function
What type of amino acids are often found at the water-lipid interface?
Charged residues
What is the key amino acid sequence conserved in all aquaporins?
Asn-Pro-Ala
Why do microbial cells require maintenance of a high concentration gradient of potassium?
To survive
What type of secondary structure interactions do β-barrel membrane proteins maximize?
Secondary structure interactions
What is the mechanism by which Valinomycin selectively binds potassium?
By electrostatic interactions with potassium ions
What causes a widespread conformational change in the calcium pump of sarcoplasmic reticulum?
Phosphorylation of Asp351
Which type of transporters are ATP-binding cassette (ABC) transporters responsible for?
Both active transport and facilitated diffusion
What do positive hydropathy windows for 20 residues in a row indicate?
Presence of a transmembrane domain
Why is it harder to obtain high quality structural information for membrane bound proteins compared to freely soluble ones?
Their hydrophobic regions interact with the aqueous environment
What allows helix bundling in proteins like GLUT1 and E. coli lactose permease?
Hydrogen bonding to glucose in channel region
Which amino acid residues do kinases catalyze the reversible phosphorylation of within other proteins?
Serine, threonine, tyrosine
What is the primary role of reversible phosphorylation by kinases in biological signalling?
Modulating enzymatic activity
What differentiates Type III integral membrane proteins from Type IV?
Number of transmembrane helices
What do positive hydropathy windows for 20 residues in a row indicate in membrane proteins?
Involvement of transmembrane domains
What is the mechanism by which Valinomycin selectively binds potassium?
Facilitation of passive potassium transport
Why is it harder to obtain high quality structural information for membrane bound proteins compared to freely soluble ones?
Reduced stability of membrane proteins in vitro
What is the primary function of membrane-bound proteins?
Signalling transduction
What is the key amino acid sequence conserved in all aquaporins?
Asn-Pro-Ala (NPA)
What is the mechanism by which Valinomycin selectively binds potassium?
It selectively binds potassium via its carbonyl oxygen atoms
What differentiates Type III integral membrane proteins from Type IV?
The number of transmembrane helices they have
What causes a widespread conformational change in the calcium pump of sarcoplasmic reticulum?
Phosphorylation of Asp351
What is the significance of the fluid mosaic model in membrane biology?
It describes the dynamic nature of membrane structure and function
What is the primary function of kinases in biological signaling?
Catalyzing reversible phosphorylation of specific residues within other proteins
What is the role of lipid anchors in membrane proteins?
To provide stability and anchoring to the lipid bilayer
Why is it harder to obtain high quality structural information for membrane bound proteins compared to freely soluble ones?
Due to challenges in solubilizing and stabilizing membrane proteins for structural studies
What is the primary function of reversible phosphorylation by kinases in biological signalling?
Modulation of enzymatic activity, protein tertiary and quaternary structure, and protein-protein interactions.
Why is it harder to obtain high quality structural information for membrane-bound proteins compared to freely soluble ones?
The hydrophobic nature of the membrane makes it difficult to obtain high quality structural information.
What differentiates Type III integral membrane proteins from Type IV?
Type III involves multiple transmembrane helices within a single polypeptide, while Type IV involves multiple polypeptide chains.
What happens as a result of reversible phosphorylation of specific residues by kinases?
It leads to a change in sterics and electronics, affecting protein tertiary and quaternary structure, as well as protein-protein interactions.
What is the key amino acid sequence conserved in all aquaporins?
Asn-Pro-Ala (NPA) motif.
What is the primary role of membrane-bound proteins in biological systems?
To serve as receptors, display enzymatic activity, and play a role in modulation of enzymatic activity.
What is the average hydropathy of the 7-amino acid sequences taken and plotted in hydropathy plots?
The average hydropathy of 7-amino acid sequences is taken and plotted.
What is the significance of the fluid mosaic model in membrane biology?
The fluid mosaic model helps in understanding the structure and function of cell membranes.
What differentiates Type V and Type VI integral membrane proteins?
Types V and VI integral membrane proteins involve covalent lipid anchors.
What is the main function of membrane-bound proteins in biological systems?
Membrane-bound proteins modulate enzymatic activity and serve as receptors.
What causes a widespread conformational change in the calcium pump of sarcoplasmic reticulum?
Phosphorylation of Asp351 causes a widespread conformational change.
What is the mechanism by which Valinomycin selectively binds potassium?
Valinomycin selectively binds K via its carbonyl oxygen atoms.
What is the role of lipid anchors in membrane proteins?
Lipid anchors in membrane proteins provide a means for membrane attachment.
What differentiates Type III integral membrane proteins from Type IV?
Type III integral membrane proteins involve helical bundles, while Type IV are β-barrel membrane proteins.
What type of secondary structure interactions do β-barrel membrane proteins maximize?
β-barrel membrane proteins maximize secondary structure interactions to maximize stability.
What is the key amino acid sequence conserved in all aquaporins?
The key amino acid sequence conserved in all aquaporins is Asn-Pro-Ala (NPA).
What is the primary role of reversible phosphorylation by kinases in biological signaling?
Reversible phosphorylation by kinases regulates the activity of other proteins in signaling pathways.
What do positive hydropathy windows for 20 residues in a row indicate in membrane proteins?
Positive hydropathy windows for 20 residues in a row indicate the presence of a transmembrane domain.
Test your knowledge on membrane bound proteins and signalling pathways from Dr. Mark Gray's lecture slides for MPharm PHA111. The quiz covers topics such as reversible phosphorylation and its role in biological signalling pathways.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
