Week 1, Lecture 1: Intro to Protein Structure Flashcards
How are peptide bonds formed?
amino acids through a condensation reaction to generate the primary sequence
what are weak noncovalent interactions btwn AAs?
Hydrophobic interaction, and hydrogen bonds and ionic interactions
what can change the ionization in the R groups, changing enzyme activity?
pH, heat
what are Two most common forms of secondary structures?
alpha helices and beta-sheet
Describe Myoglobin, type of protein and # of helices…
Globular protein, 8
One type secondary structure make what type of protein?
Globular (most compactly folded), NOT fibrous
Proteins that have similar folds often have similar…..
functions
Myoglobin transports O2 to ____ for storage.
mitochondria
Hemoglobin transports O2 from ___ to ___.
lungs to tissues
What are some factors that might cause a protein to unfold?
Oxidative damage, organic solvents, changes in pH, or changes in temperature can cause proteins to denature
Denaturation exposes hydrophobic residues which can then lead to….?
aggregation making the protein insoluble
eg. heinz bodies
Can you name any diseases associated with protein aggregation?
Alzheimers, parkinsons, type II diabetes, cancer
what happens in Prion diseases?
like Creutzfeldt-Jakob disease, proteins exhibit an increase in beta-sheets.
Whats the result of An increase in beta-sheets?
leads to self-association and the formation of amyloid fibers
Molecular chaperones are used by the cell for what?
to prevent the aggregation of misfolded proteins
multiple polypeptide chains?
quaternary structure
hemoglobin has how many alpha and beta chains?
[α(2):β(2)]
tetrameric hemeprotein
Positive cooperativity results in what shape?
sigmoid shaped curve
Is an allosteric modulator that promotes T state?
2,3-bisphosphoglycerate: at high altitudes
BPG levels increase
what kind of posttranslational modifications can alter protein structure and function?
carbohydrate addition, lipid addition, regulation
what happens when there is a decrease in glycosylation?
higher turn over of RBC
what is a glycosylated protein called that can for a large protein aggregate?
advanced glycation end products
Glycosylation of hemoglobin (irreversible) has little effect on function but glycosylation of collagen in the heart results in ???
cardiomyopathy
Sickle cell anemia can be caused by a point mutation converting ____ to ____? what position? what chain?
glutamatic acid to valine at position 6 in β chain resulting in aggregation
when is polymerization favorable?
concentration of HbS and is favored when hemoglobin is in the deoxygenated form
The polymerization of hemoglobin results in ….?
sickling of the red blood cells and anemia
sickling increases ____ of membrane and increasing _____?
Sickling increase permeability of membrane increasing intracellular Ca++
Sickling of red blood cells can result in what effects?
occlusion of red blood vessels leading to organ damage and stroke, hypoxia»_space;> necrosis
Sickle cell disease onset occurs at approximately what age?
four months when hemoglobin switching occurs
HbF has reduced
Affinity for?
BPG
Glu6Val
HbS
(α2β2S) sickle cell disease/anemia
HbSS
(α2β2A) normal
HbAA
sickle cell trait; only 1% of cells sickled
HbSA
Glu6Lys
HbC
compound heterozygous sickle cell disease
HbSC
result from altered ratio of alpha: beta globin
Thalassemias
