Flashcards
Hb and retinal binding protein
Cards in this deck (13)
- 1on oxygenation the distance between iron atoms in b chains ____? deoxyghaemoglobin is the ___ state and oxyhaemoglobin is the ____ state?decreases from 3.99 to 3.34 nm
deoxyghaemoglobin is the tense state
and oxyhaemoglobin is the relaxed state? - 2deoxyghaemoglobin, T-state is constrained and stabilized by ___ and ____, which involved ______?stabilized by hydrophobic bonds and 8 electrostatic bonds,
which involved the C-terminal basic AA's of each subunit - 3each of the penultimate (2nd last) Tyr residues is held in a pocket by what bonding to ___? what does this do? what further stabilizes the T state?H bonding to Val,
this anchors the C-terminal residues in positions favourable for electrostatic bond formation.
2,3-BPG between b-subunits further stabilizes the T-state - 4in deoxyghaemoglobin, the proximal His F8 is bonded to the iron but the Fe'' is above the plane by 0.06 nm when oxygen bind to iron, what happens?the iron pulls it 0.039 nm closer into the porphyrin plane
- 5upon binding to O2, as the iron moves it drags the His F8, so what happens?the helix F and EF cover and FG corner follow
these movements are transmitted to the subunit interfaces and result in the breaking of the 8 electrostatic bonds - 6a new conformation upon boning. a shift in helix F results in?results in that and last tyrosine residue pop out of the H-bonded pocket with Valines ***breaking the electrostatic bonds (that stabilize the T state)
*** a1b1 subunit rotates by 15 degree with respect to the a2b2
= relaxed R state - 8 electrostatic bonds broken, and b subunits are closer and the site of 2,3-BPG no longer there - 7Oxygen binds to Fe'' causese 1. 2. 3. 4. 5.1. pulls the proximal HIs in the F helix
2. changes are transmitted to the subunit interfaces
3. 8 electrostatic bonds broken
4. 2,3-BPG site lost
5. ab subunit rotates by 15 degrees with respect to the other - 8retinol = vitamin A, is? where its made and transported by?lipid alcohol
made in the liver, and transported to Vitamin A-dependent tissues by
retinol binding protein - 9retinol is one of several active forms of Vitamin A, it is derived from? cleaved by? and can be store in the liver as?derived from b-carotenes synthesized by plants
cleaved to retinol by most animals
can be stored in the liver as retionl palmitate - 10vitamin is important as? 1. 2. 3.1. anti-oxidant
2. a steroid hormone
3. vital component of night vision - 11retinol binding protein's Mr 21000 it is what kind of protein? which composes of what topology?it is a beta-domain protein
up-and-down beta-barrel with 8 strands in a simple topology (arrangement) - 12the retinol binding site is lined with _____? for example?lined with hydrophobic residues
such as Phe, Met, and Tyr - 13retinol is bound by ___ and this binds to _________, which does what?retinol is bound by RBP (retinol binding protein), then bind to transthyretin (large mlc), which stabilizes it and prevent its loss by the kidney and transports it to cell-surface receptors which recognize the entire complex
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- biological sciences Biol 115 Flashcards on Hb and retinal binding protein, created by Jenny Lee7018 on 15/05/2016.
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