11:115:301 Lecture Notes - Lecture 5: Alpha Helix, Globular Protein, Myoglobin
22 Sep 2019
School
Department
Course
Professor
Document Summary
Used as model for proteins + enzymes simple. Hb"s 4 chains are 10x better than myoglobin at o2 binding due to cooperativity of o2 binding. Held between histidines on helices e + f. Myoglobin structure is composed of 8 helices. First structure to be crystallized + atomic structure determined. Storage proteins of oxygen in muscle cells. Myoglobin fold held together by hydrophobic effect. 4 prolines only at ends of alpha helices. Cannot be in the middle of alpha helix. Not part of a or b chains. 1st aa not met end terminal modification methionine cleaved by peptidase. A lot of mb to stay underwater. A-helix in globular protein inner surface mostly hydrophobic + outer surface mostly hydrophilic. Should see cluster of hydrophobic aa"s (filmyvw) => tells you that it is helical. Can look down the barrel of alpha helix. O2 binding changes the shape of hb. Fe held by n"s of pyrrole rings.
