Journal of Diagnostics Concepts & Practice ›› 2018, Vol. 17 ›› Issue (03): 260-265.doi: 10.16150/j.1671-2870.2018.03.006

• Original articles • Previous Articles     Next Articles

Molecular mechanism of Ax subtype caused by p.M142I mutation in alpha 1-3-N-acetylgalactosaminyltransferase

WANG Dengfeng1, CUI Wenyan2, ZOU Wei3, LI Fang4, WANG Xuefeng3, CAI Xiaohong3   

  1. 1. Blood Group Reference Laboratory, Puyang Blood Center, Henan Puyang 457000, China;
    2. Department of Blood Transfusion, The Second Affiliated Hospital of Zhengzhou University, Henan Zhengzhou 450014, China;
    3. Department of Blood Transfusion, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China;
    4. State Key Laboratory of Microbial Metabolism, College of Life Science and Technology, Shanghai Jiao Tong University, Shanghai 200240, China
  • Received:2018-01-25 Online:2018-06-25 Published:2018-06-25

Abstract: Objective: To explore the potential molecular mechanism of Ax subtypes in Chinese population based on an Ax subtype family. Methods: The ABO blood group serological tests and detection of the total plasma activity of alpha α-1,3-N-acetylgalactosaminyltransferase were conducted. ABO gene was sequenced directly and sequenced after cloning to construct 3D molecular model, and then the effect of identified mutation on protein stability changes (ΔΔG) of alpha α-1,3-N-acetylgalactosaminyltransferase was predicted. Results: The proband was diagnosed as AxB subgroup byserological analysis, and AW.38/B.01 was identified by DNA analysis. His two daughters were identified as A and AB blood group, and their ABO genotypes were A1.02/B.01, A1.02/AW.38, respectively.There was a c.426G>C heterozygous mutation in ABO exon 7 of the proband and his A type daughter, leading to p.M142I change in the amino acid of α-1,3-N-acetylgalactosaminyltransferase. Molecular modeling and analysis suggested that the mutation may lead to changes in the number of hydrogen bonds formed. The increase of ΔΔG value of thermodynamic stability changes indicated that the protein stability was reduced. Conclusions: The mutation of p.M142I in α-1,3-N-acetylgalactosaminyltransferase may lead to Ax phenotype by reducing the stability of the enzyme. In vitro study is needed for further investigation.

Key words: ABO blood group, α-1, 3-N-acetylgalactosaminyltransferase, Gene mutation, Protein stability

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