P.R180C mutation of glycosyltransferase B leads to B subgroup, an in vitro and in silico study. Issue 5 (4th May 2018)

• Record Type: Journal Article
• Authors: Cai, X.; Li, F.; Lei, H.; Qu, S.; Qian, C.; Xiang, D.; Wei, D.‐Q.; Wu, W.; Xu, Q.; Wang, X.
• Is Part Of: Vox sanguinis. Volume 113:Issue 5(2018)
• Page Start: 476
• Page End: 484
• Publication Date: 2018-05-04
• Subjects: ABO -- conversion -- glycosyltransferase B -- mutation -- p.R180C; Blood -- Periodicals; Blood -- Transfusion -- Periodicals; Immunohematology -- Periodicals; Immunopathology -- Periodicals; 615.39
• DOI: 10.1111/vox.12655
• Languages: English
• ISSNs: 0042-9007

Abstract

Abstract : Background and Objectives: Dysfunctional glycosyltransferase A or B may lead to incomplete glycosylation of H antigen and atypical ABO blood group with weak A or B phenotypes, posing challenges for blood typing for transfusion. Materials and Methods: Serological studies and ABO gene analysis were performed. Flow cytometry was performed on HeLa cells transfected glycosyltransferase B expressing plasmids. Agglutination of transfected cells and total glycosyltransferase B transfer capacity were examined. Molecular dynamics simulations were used to explore possible dynamic conformational changes around the binding pocket. Results: We identified a mutation c.538C>T (p. R180C) of B allele in a Chinese donor and his father with ABw phenotype. In vitro expression study showed that mutation p.R180C, although not affecting expression of glycosyltransferase B, impaired H to B antigen conversion. The in silico analyses found that the residue Arg180 on the internal loop next to the entry of the binding pocket may have its long side chain salt‐bridged with the highly flexible C‐terminal carboxyl and contribute to the catalysis of H to B antigen conversion. Conclusion: The p.R180C mutation impairs the conversion from H to B antigen and leads to weak B phenotype. Dynamic interaction between Arg180 and C‐terminal of glycosyltransferase B may stabilize its binding with UDP‐galactose and facilitate H/B antigen conversion.