Abstract: Objective To analyze the types and frequencies of B(A) subtype alleles in the Dalian area, and to perform spatial structure prediction and molecular dynamics simulation of transferase using computational tools. Methods Initially, 18 samples exhibiting serological characteristics of the B(A) subtype were screened by serological methods. The full-length ABO gene and its flanking regulatory regions were then sequenced using PacBio third-generation technology. Finally, computer software was used to predict the spatial structure of the transferase and conduct molecular dynamics simulations. Results Among 18 B(A) samples detected, only 1 carried the BA.02 allele, 13 contained the BA.04 allele, and 4 had a novel BA.NEW (c.797T>C) allele not yet included in the ISBT database. The frequencies of the B(A) subtype alleles in the Dalian area were as follows: BA.02-2.94%, BA.04-38.24%, and BA.NEW-8.82%. The BA.04 allele was dominant, while the BA.02 allele was relatively rare. Molecular dynamics simulations of wild-type B transferase and BA.NEW encoded B(A)-c.797C transferase in a "closed" conformation suggested that amino acid substitutions at position 266 could induce changes in the surrounding spatial conformation, affecting enzyme function and activity. Additionally, molecular dynamics simulations further indicated that the binding between B(A)-c.797C transferase and ligand became unstable. Conclusion Three alleles in the B(A) subtype were identified in the Dalian area, i.e. BA.02, BA.04, and BA.NEW, with BA.04 being significantly more prevalent than BA.02. The newly discovered BA.NEW allele enriches the genetic diversity of the ABO blood group system. Molecular dynamics simulations revealed that the ligand binding of the B(A)-c.797C transferase encoded by BA.NEW is unstable.

Key words: B(A) subtype, Third-generation sequencing, Allele, Molecular dynamics, Prediction