University:
Amherst College
Course:
BIOL 330 | Biochemical Principles of Life at the Molecular Level
Academic year:

2010
Views:

454

Pages:

17
Author:

Jordin Calderon

Myoglobin This lecture • Myoglobin Background – What does it do? • Myoglobin Structure – Lots of helices • Myglobin FuncDon – Oxygen binding Background • What does Myoglobin do? – Found in muscles. – Whales have a lot of it. Purpose in Muscles Myoglobin Structure • 153 (154) residues long, one polypepDde chain. • 17.2 KDa in “apo” form • Primary Sequence 1 mglsdgewql vlnvwgkvea dipghgqevl irlXghpet lekfdkXhl ksedemkase 61 dlkkhgatvl talggilkkk ghheaeikpl aqshatkhki pvkyleﬁse ciiqvlqskh 121 pgdfgadaqg amnkalelfr kdmasnykel gfqg DistribuDon of amino acids 8 14 12 20 9 3 7 7 4 2 22 31 23 12 15 7 17 8 5 7 3 2 1 77 Myglobin Structure • A Helical protein. 1 GLSDGEWQL VLNVWGKVEA DIPGHGQEVL IRLFKGHPET LEKFDKFKHL KSEDEMKASED B A C D 61 LKKHGATVL TALGGILKKK GHHEAEIKPL AQSHATKHKI PVKYLEFISE CIIQVLQSKHP E F 121 GDFGADAQG AMNKALELFR KDMASNYKEL GFQG H Length of helix? G Myglobin Structure Myoglobin binds Heme Heme is Dghtly bound Myglobin Structure – Heme bound Structure = FuncDon So: Myoglobin binds Heme Heme binds O2 O2 Exchanges from Hb to Mb • HEMOGLOBIN • MYOGLOBIN •Crystal structure is very complicated. •Crystal structure is very simple •Hb protein is four subunits, four heme groups, and seems to behave differently when all together as compared with monomers. •Oxygen saturation curve is “sigmoidal” complicated mathematical formula. O2 •Mb protein is one subunit, one heme, and behaves simply •Oxygen saturation curve is hyperbolic, which mathematically is quite simple y= x/(a+x) Key concepts of equilibrium binding To the Board! Key concepts of equilibrium binding • Picking up pens. • How does this compare to protein catalysis? • A + B AB  A + C • A + B AB More on Binding Wednesday! • How Hb is diﬀerent from Mb. • What that means in sequence, structure, and funcDon. • Problem sets on the way…

Myoglobin - Lecture Notes

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