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UniProtKB/Swiss-Prot variant pages

UniProtKB/Swiss-Prot P16442: Variant p.Asp291Asn

Histo-blood group ABO system transferase
Gene: ABO
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Variant information Variant position: help 291 The position of the amino-acid change on the UniProtKB canonical protein sequence.
Type of variant: help LB/B The variants are classified into three categories: LP/P, LB/B and US.
  • LP/P: likely pathogenic or pathogenic.
  • LB/B: likely benign or benign.
  • US: uncertain significance

Residue change: help From Aspartate (D) to Asparagine (N) at position 291 (D291N, p.Asp291Asn). Indicates the amino acid change of the variant. The one-letter and three-letter codes for amino acids used in UniProtKB/Swiss-Prot are those adopted by the commission on Biochemical Nomenclature of the IUPAC-IUB.
Physico-chemical properties: help Change from medium size and acidic (D) to medium size and polar (N) The physico-chemical property of the reference and variant residues and the change implicated.
BLOSUM score: help 1 The score within a Blosum matrix for the corresponding wild-type to variant amino acid change. The log-odds score measures the logarithm for the ratio of the likelihood of two amino acids appearing by chance. The Blosum62 substitution matrix is used. This substitution matrix contains scores for all possible exchanges of one amino acid with another:
  • Lowest score: -4 (low probability of substitution).
  • Highest score: 11 (high probability of substitution).
More information can be found on the following page

Polymorphism: help Genetic variations in ABO define the ABO blood group system [MIM:616093]. The ABO blood group system is the most important blood group system in blood transfusion. The sequence shown here is that of the A transferase. The B form differs by a few residues substitution. Residues 266 and 268 are important for specificity. The reference genome assembly (GRCh38/hg38) describes a non-functional O-type ABO allele. The O-type ABO allele results in a guanine deletion (NM_020469.2: c.286delG). This deletion induces a frameshift and creates a premature stop codon resulting in a truncated (117 amino acids) protein deprived of any glycosyltransferase activity (PubMed:2333095). Additional information on the polymorphism described.
Variant description: help In allele B104. Any additional useful information about the variant.


Sequence information Variant position: help 291 The position of the amino-acid change on the UniProtKB canonical protein sequence.
Protein sequence length: help 354 The length of the canonical sequence.
Location on the sequence: help GGSVQEVQRLTRACHQAMMV D QANGIEAVWHDESHLNKYLL The residue change on the sequence. Unless the variant is located at the beginning or at the end of the protein sequence, both residues upstream (20) and downstream (20) of the variant will be shown.
Residue conservation: help The multiple alignment of the region surrounding the variant against various orthologous sequences.
Human                         GGSVQEVQRLTRACHQAMMVDQANGIEAVWHDESHLNKYLL

Mouse                         GGSVLEVYHLTKACHEAMMEDKANGIEPVWHDESYLNKYLL

Sequence annotation in neighborhood: help The regions or sites of interest surrounding the variant. In general the features listed are posttranslational modifications, binding sites, enzyme active sites, local secondary structure or other characteristics reported in the cited references. The "Sequence annotation in neighborhood" lines have a fixed format:
  • Type: the type of sequence feature.
  • Positions: endpoints of the sequence feature.
  • Description: contains additional information about the feature.
TypePositionsDescription
Chain 1 – 354 Histo-blood group ABO system transferase
Chain 54 – 354 Fucosylglycoprotein alpha-N-acetylgalactosaminyltransferase soluble form
Topological domain 54 – 354 Lumenal
Active site 303 – 303 Nucleophile
Binding site 303 – 303
Mutagenesis 303 – 303 E -> A. Decreases specific activity of group B transferase almost to zero.
Helix 274 – 293



Literature citations
Molecular genetic analysis of variant phenotypes of the ABO blood group system.
Ogasawara K.; Yabe R.; Uchikawa M.; Saitou N.; Bannai M.; Nakata K.; Takenaka M.; Fujisawa K.; Ishikawa Y.; Juji T.; Tokunaga K.;
Blood 88:2732-2737(1996)
Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA] OF 81-354; POLYMORPHISM; VARIANTS LEU-156; GLY-176; ARG-214; ILE-216; ASP-223; SER-235; MET-266; ALA-268; MET-277; ASN-291; GLY-352 AND TRP-352;
Disclaimer: Any medical or genetic information present in this entry is provided for research, educational and informational purposes only. They are not in any way intended to be used as a substitute for professional medical advice, diagnostic, treatment or care.