BCH 4024 Lecture Notes - Lecture 8: Conformational Change, Kolmogorov Space, Heme

• School: University of Florida
• Department: Biochemistry and Molecular Biology
• Course: BCH 4024
• Professor: Daniel L Purich

Document Summary

Hb occurs in two conformationally constrained states: There are no hybrid forms (i. e. , none containing both t and r subunits. ) T-state (hb-t) has little or no affinity for o2. R-state (hb-r) has good affinity for o2. T0-state is greatly favored compared to r0-state, when there is no bound o2(i. e. , [t0]/[r0] 700). O2 binding stabilizes r-state, thereby increasing population of hb subunits in the r-state. Conformational changes are transmitted across subunit-subunit interface. R0 can because o2 only binds when fe2+ is in the plane of the heme ring. Conformational change is transmitted through peptide backbone, changing tertiary structure of entire subunit. Strongly influenced by several well placed salt bridges. All-or-none transition between hemoglobin"s t0 & r0 states. T0acts to buffer the concentration of r0during oxygenation. Equivalent o2 affinity to r0, r1, r2, & r3 forms of hb. Solvent molecules are always colliding into hb,giving and taking energy.