Carboxyl-terminal modification influences subunit assembly of sickle hemoglobin beta chains.
The subunit assembly properties of isolated beta and Des(His-146,Tyr-145) beta chains of sickle hemoglobin were investigated by isoelectric focusing over a protein concentration range from 500-125 microM in heme. Two components (presumably tetramer and monomer) and three components (designated tetramer, dimer and monomer) were visualized for beta s and Des(His-146,Tyr-145) beta s chains, respectively. Intensitometric quantitation of Des(His-146,Tyr-145) beta s chains demonstrated a similar distribution of all three structural components before and after the addition of their heteropartner alpha chains. This is in direct contrast to the reported preferential loss of Des(His-146,Tyr-145) beta A monomer species upon assembly and points to a major role of the beta 6 residue in the overall structural homeostasis of carboxylterminal modified human beta chains.
Moulton
D P
DP
Department of Chemistry, College of Arts and Sciences, University of Massachusetts, Lowell 01854, USA.
Morris
A
A
Vasudevan
G
G
Chiu
F
F
McDonald
M J
MJ
D001704:Biopolymers; D006451:Hemoglobin, Sickle / Q000138:chemical synthesis / Q000737:chemistry*; D006801:Humans; D007525:Isoelectric Focusing; D011487:Protein Conformation
D001704:Biopolymers; D006451:Hemoglobin, Sickle