Lehninger principles fig 5 20b light blue s subunits

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Unformatted text preview: residue 6 from Glu to Val) Residue 6 is at surface of β chain. Hydrophobic Val 6 on β subunit of 1 tetramer sticks to patch on T state β subunit of another tetramer. Residues in pocket, patch T state but not R state HbS has a hydrophobic “pocket” on β surface, present also on normal deoxyHb β, that the βS Val 6 “knob” sticks to. So tetramers of deoxy (but not oxy) HbS aggregate Berg, Tymoczko & Stryer, Biochemistry, 6th ed, Fig. 7-25 http://www.biochem.arizona.edu/classes/bioc462/462a/jmol/hbs/hbs1.htm HbS aggrega:on Hydrophobic pocket Each tetramer has 2 β subunits = 2 knobs, 2 hydrophobic patches. β Val6 This allows propagation of aggregation Formation of long, rigid insoluble fibers of HbS under conditions of low O2 Q: How is this different from amyloid-type aggregation? Lehninger Principles, Fig. 5-20b light blue = βS subunits DeoxyHbS aggregationred blood cell sickling Long fibers distort shape of red blood cells, sickleshaped cells clog capillaries, poking holes i...
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This test prep was uploaded on 02/25/2014 for the course BIOC 462A taught by Professor Ziegler,baldwin during the Spring '08 term at University of Arizona- Tucson.

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