TY - JOUR
T1 - Extension arm facilitated pegylation of αα-hemoglobin with modifications targeted exclusively to amino groups
T2 - Functional and structural advantages of free cys-93(β) in the PEG-Hb adduct
AU - Li, Dongxia
AU - Hu, Tao
AU - Manjula, Belur N.
AU - Acharya, Seetharama A.
PY - 2009/11/18
Y1 - 2009/11/18
N2 - Cys-93(β) of hemoglobin (Hb) was reversibly protected as a mixed disulfide with thiopyridine during extension arm facilitated (EAF) PEGylation and its influence on the structural and functional properties of the EAF-PEGHb has been investigated. Avoiding PEGylation of Cys-93(β) in the EAF-PEG-Hb lowers the level of perturbation of heme pocket, α1β2 interface, autoxidation, heme loss, and the O2 affinity, as compared to the EAF-PEG-Hb with PEGylation of Cys-93(β).The structural and functional advantages of reversible protection of Cys-93(β) during EAF PEGylation of oxy-Hb has been compared with Euro PEG-Hb generated by EAF PEGylation of deoxy Hb where Cys-93(β) is free in the final product. The αα-fumaryl cross-linking and EAF PEGylation targeted exclusively to Lys residues has been combined together for generation of second-generation EAF-PEG-Hb with lower oxygen affinity. The PEG chains engineered on Lys as well as PEGylation of Cys-93(β) independently contribute to the stabilization of oxy conformation of Hb and hence increase the oxygen affinity of Hb. However, oxygen affinity of the EAF-PEG-αα-Hb is more sensitive to the presence of PEGylation on Cys-93(β) than that of the EAF-PEG-Hb. The present modified EAF PEGylation platform is expected to facilitate the design of novel versions of the EAF-PEG-Hbs that can now integrate the advantages of avoiding PEGylation of Cys-93(β).
AB - Cys-93(β) of hemoglobin (Hb) was reversibly protected as a mixed disulfide with thiopyridine during extension arm facilitated (EAF) PEGylation and its influence on the structural and functional properties of the EAF-PEGHb has been investigated. Avoiding PEGylation of Cys-93(β) in the EAF-PEG-Hb lowers the level of perturbation of heme pocket, α1β2 interface, autoxidation, heme loss, and the O2 affinity, as compared to the EAF-PEG-Hb with PEGylation of Cys-93(β).The structural and functional advantages of reversible protection of Cys-93(β) during EAF PEGylation of oxy-Hb has been compared with Euro PEG-Hb generated by EAF PEGylation of deoxy Hb where Cys-93(β) is free in the final product. The αα-fumaryl cross-linking and EAF PEGylation targeted exclusively to Lys residues has been combined together for generation of second-generation EAF-PEG-Hb with lower oxygen affinity. The PEG chains engineered on Lys as well as PEGylation of Cys-93(β) independently contribute to the stabilization of oxy conformation of Hb and hence increase the oxygen affinity of Hb. However, oxygen affinity of the EAF-PEG-αα-Hb is more sensitive to the presence of PEGylation on Cys-93(β) than that of the EAF-PEG-Hb. The present modified EAF PEGylation platform is expected to facilitate the design of novel versions of the EAF-PEG-Hbs that can now integrate the advantages of avoiding PEGylation of Cys-93(β).
UR - http://www.scopus.com/inward/record.url?scp=71249139373&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=71249139373&partnerID=8YFLogxK
U2 - 10.1021/bc900170e
DO - 10.1021/bc900170e
M3 - Article
C2 - 19842622
AN - SCOPUS:71249139373
SN - 1043-1802
VL - 20
SP - 2062
EP - 2070
JO - Bioconjugate Chemistry
JF - Bioconjugate Chemistry
IS - 11
ER -