Protein Structure/Hemoglobin/Collagen Flashcards
What are three chemical interactions that maintain protein structure?
Hydrophobic interaction
Hydrogen bonds
Electrostatic interactions
What amino acids can be phosphorylated and why?
Serine, Tyrosine, Threonine
Because they have OH hydroxyl groups
What amino acid genetic mutation causes sickle cell anemia?
glutamine (-) to valine (neu)
What is the lifetime of a healthy red blood cell?
120 days
What is different about HbA1c?
It is glycosylated on the N-terminal valine of the beta chain.
What hemoglobin form is used to measure blood glucose levels in diabetics?
HbA1c
Oxygen binds to what oxidation state of Fe in hemoglobin?
Fe+2
In terms of hemoglobin, what is positive cooperativity?
Binding the first O2 increases affinity of the other subunits
What are tense and relaxed states of Hb subunits?
Tense = low O2 affinity Relaxed = high O2 affinity
What does low pH do to Hb O2 affinity?
decreases it
What is the most abundant protein in mammals
collagen
What is the basic structural unit fo collagen?
3 strand helix called tropocollagen
The distribution of what hydrophobic aa side chain forces collagen into a left hand helix.
Proline
What does vitamin C (ascorbate) used for in collagen?
It reduces proline to hydroxyproline.
Hydroxyproline increases stability of the triple helix via hydrogen bonds.
Collagen is strengthened by covalent cross links from what amino acid side chain?
Lysine
How does copper deficiency affect collagen?
Lysine cross links do not form
Why does collagen need cross links?
Without them collagen is susceptible to proteases
Osteogenesis Imperfecta
Defective collagen
brittle bones
Ehlers-Danlos syndrome
Connective tissue problems due to collagen defects
Vitamin D synthesis in the body is initiated by what?
UVB rays
Vitamin D is synthesized from what molecule?
cholesterol
Low calcium stimulates the release of what hormone?
Parathyroid Hormone (PTH)
What is the active form of vitamin D?
1,25-Dihydroxycholecalciferol
calcitriol
Where to steroid hormones bind to their receptors?
Inside of the cell
What does vitamin D (calcitriol) do in the body?
It helps to regulate calcium concentration in the blood.
Calcitriol stimulates bones to uptake calcium for bone growth and maintenance. PTH does the opposite
