48 Questions
What type of protein structure is characterized by local conformations maintained by extensive hydrogen bonding involving the peptide bond components?
Secondary structure
Which type of secondary structure in proteins is described as 'helical and coiled'?
α-helix
Which bond in the protein structure allows free rotation between the alpha-carbon and amino nitrogen in a residue?
Phi bond
In an α-helix, how are the hydrogen bonds oriented with respect to the helix axis?
Parallel
Which type of secondary protein structure forms 'extended flat sheets'?
β-sheet
What pattern of hydrogen bonds helps form secondary structures like α-helices and β-strands?
Hydrogen bonds
What stabilizes the tertiary (3°) structure of a protein?
Interactions of amino acid side chains in non-neighboring regions
What type of proteins often combine alpha-helix and beta-sheets in their structure?
Globular proteins
Which protein structure is characterized by interactions of amino acid side chains in non-neighboring regions?
Tertiary structure
What is the main cause of denaturation known as protein unfolding?
Changes in side chain electrostatics
Which health condition is mentioned as an example associated with denaturation?
Parkinson's Disease
What is the term used to describe the effect where non-polar species in water reduce entropy?
Hydrophobic Effect
Which type of proteins have hydrophobic residues inside and play a role in disrupting protein folding?
Membrane proteins
What type of bond is formed between the C=O of amino acid #1 and N-H of amino acid #5 in an alpha helix structure?
Hydrogen bond
What disrupts an alpha helix structure by creating a bend or 'kink'?
Proline
How many amino acids typically make up one turn of an alpha helix structure?
3.6 amino acids
What is the distance of one turn repeat in an alpha helix structure?
5.4Å
In a beta-pleated sheet, what type of bonds form between the backbones of adjacent polypeptide chains?
Hydrogen bonds
Which amino acid is commonly found in reverse turns of protein structures due to steric reasons?
Glycine
What is the effect of 2,3-BPG on hemoglobin?
Inhibits Hb from binding to oxygen
How does the presence of 2,3-BPG affect the affinity of hemoglobin for oxygen?
Decreases the affinity of hemoglobin for oxygen
What is the role of 2,3-BPG in red blood cells?
It binds to hemoglobin at a 1:1 molar ratio
How is protein structure typically determined?
Through X-ray diffraction of protein crystals
Which factor markedly decreases hemoglobin's affinity for oxygen?
Increasing the binding of 2,3-BPG to Hb
What disrupts an alpha helix structure by creating a bend or 'kink'?
Steric crowding from bulky side chains like Val, Ile, Thr
What type of secondary structure involves polypeptide chains lying adjacent to one another in a sheet-like structure?
Beta-pleated sheet
What factor contributes to disrupting an alpha helix structure due to restricted rotation and lack of N-H for hydrogen bonding?
Proline's cyclic structure and lack of N-H for hydrogen bonding
In a beta-pleated sheet, what type of bonds form between the backbones of adjacent polypeptide chains?
Hydrogen bonds
What is the distance of one turn repeat in an alpha helix structure?
5.4 Å
Which amino acid is commonly found in reverse turns of protein structures due to steric reasons?
Glycine
What is the major type of secondary structure in proteins formed by a regular pattern of hydrogen bonds between amide N-H and C=O groups of amino acids near each other in the primary sequence?
α-helix
Which bond in protein structure allows free rotation between the α-carbon and amino nitrogen in a residue?
Peptide bond
What is the characteristic feature of β-sheets in protein secondary structure?
Extended 'flat' sheet structure
In an α-helix, how are the hydrogen bonds oriented with respect to the helix axis?
Parallel
What type of bonds hold together α-helices both intrachain and interchain?
Hydrogen bonds
Which component of proteins plays a crucial role in maintaining local conformation through extensive hydrogen bonding involving peptide bond components?
Amide H of the peptide backbone
What is the primary (1°) structure of a protein referring to?
The sequence of amino acids in a polypeptide chain
In protein folding, which force is considered a stabilizing force due to its interactions with non-polar residues?
Hydrophobic effect
What percentage of human proteins is post-transcriptionally modified?
60%
Which level of protein structure involves the way the polypeptide chain folds up in three-dimensional space?
Tertiary structure
What is the primary structural difference between Hemoglobin and Hemoglobin2ia mentioned in the text?
Destabilizing force in Hemoglobin2ia
What causes Parkinson's disease according to the text?
Misfolding of proteins in bacteria
What is the main goal of the CASP challenge?
To improve computational methods for predicting protein structures
Which factor is NOT a common cause of protein denaturation?
Increasing hydrogen bonding with urea/guanidine
What can contribute to diseases like Alzheimer's and Diabetes type 2?
Protein aggregation linked to neurodegenerative diseases
Which process can proteins undergo if denaturation is not too severe?
Renaturation back to the native structure
What is a significant effect of non-polar species on water in terms of protein folding?
Decrease in entropy as water organizes around non-polar species
Which type of proteins are often linked to disrupting protein folding?
Proteins with hydrophobic residues inside
Test your knowledge on proteins and their structural motifs. Explore the concept of multifunctional proteins, different motifs, domains, and interactions in tertiary structures.
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