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UniProtKB/Swiss-Prot P07359: Variant p.Ala254Ser

Platelet glycoprotein Ib alpha chain
Gene: GP1BA
Variant information

Variant position:  254
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Type of variant:  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:  From Alanine (A) to Serine (S) at position 254 (A254S, p.Ala254Ser).
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:  Change from small size and hydrophobic (A) to small size and polar (S)
The physico-chemical property of the reference and variant residues and the change implicated.

BLOSUM score:  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:  Position 161 is associated with platelet-specific alloantigen Siba (PubMed:1586750). Siba(-) has Thr-161 and Siba(+) has Met-161 (PubMed:1586750). Siba is involved in neonatal alloimmune thrombocytopenia (NATP) (PubMed:1586750, PubMed:7632942).Polymorphisms arise from a variable number of tandem 13-amino acid repeats of S-E-P-A-P-S-P-T-T-P-E-P-T in the mucin-like macroglycopeptide (Pro/Thr-rich) domain (PubMed:1577776, PubMed:7632942). Allele D contains one repeat starting at position 415, allele C contains two repeats, allele B (shown here) contains three repeats and allele A contains four repeats (PubMed:1577776). Allele B is associated with susceptibility to nonarteritic anterior ischemic optic neuropathy (PubMed:1577776). -
Additional information on the polymorphism described.

Other resources:  
Links to websites of interest for the variant.

Sequence information

Variant position:  254
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Protein sequence length:  652
The length of the canonical sequence.

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: 
The multiple alignment of the region surrounding the variant against various orthologous sequences.




Sequence annotation in neighborhood:  
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.

Chain 17 – 652 Platelet glycoprotein Ib alpha chain
Chain 17 – 506 Glycocalicin
Topological domain 17 – 531 Extracellular
Domain 221 – 282 LRRCT
Disulfide bond 225 – 264
Disulfide bond 227 – 280
Mutagenesis 249 – 249 G -> A. No change.
Mutagenesis 249 – 249 G -> KD. Decreased binding to vWF.
Mutagenesis 249 – 249 G -> SV. Increased binding to vWF.
Helix 252 – 254

Literature citations

No reference for the current variant in UniProtKB/Swiss-Prot.

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.