Protection of aquo/hydroxocobalamin from reduced glutathione by a B12 trafficking chaperone

BMB Reports

Tal Soo Ha^2¹  Jinju Jeong^1² 

[1] Department of Biomedical Science, College of Natural Science, Daegu University, Gyeongsan 712-714, Korea^2;School of Biotechnology, Yeungnam University, Gyeongsan 712-749^1

关键词: Cobalamin;   

DOI  :  

学科分类：生物化学/生物物理

来源: Korean Society for Biochemistry and Molecular Biology

【 摘 要 】

We identified a bovine B(12) trafficking chaperone bCblC in Bos taurus that showed 88% amino acid sequence identity with a human homologue. The protein bCblC was purified from E. coli by over-expression of the encoding gene. bCblC bound cyanocobalamin (CNCbl), methylcobalamin (MeCbl) and adenosylcobalamin (AdoCbl) in the base-off states and eliminated the upper axial ligands forming aquo/hydroxocobalamin (OH(2)/OHCbl) under aerobic conditions. A transition of OH(2)/OHCbl was induced upon binding to bCblC. Interestingly, bCblC-bound OH(2)/OHCbl did not react with reduced glutathione (GSH), while the reaction of free OH(2)/OHCbl with GSH resulted in the formation of glutathionylcobalamin (GSCbl) and glutathione disulfide (GSSG). Furthermore we found that bCblC eliminates the GSH ligand of GSCbl forming OH(2)/ OHCbl. The results demonstrated that bCblC is a B(12) trafficking chaperone that binds cobalamins and protects OH(2)/OHCbl from GSH, which could be oxidized to GSSG by free OH(2)/OHCbl.

【 授权许可】

Unknown