UniProtKB/Swiss-Prot P01008: Variant p.Met121Lys

Antithrombin-III
Gene: SERPINC1
Chromosomal location: 1q23-q25.1
Variant information

Variant position:  121
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Type of variant:  Disease [Disclaimer]
The variants are classified into three categories: Disease, Polymorphism and Unclassified.
  • Disease: Variants have been found in patients and disease-association is reported in literature. However, this classification is not a definitive assessment of variant pathogenicity.
  • Polymorphism: No disease-association has been reported.
  • Unclassified: Variants have been found in patients but disease-association remains unclear.

Residue change:  From Methionine (M) to Lysine (K) at position 121 (M121K, p.Met121Lys).
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 medium size and hydrophobic (M) to large size and basic (K)
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

Involvement in disease:  Antithrombin III deficiency (AT3D) [MIM:613118]: An important risk factor for hereditary thrombophilia, a hemostatic disorder characterized by a tendency to recurrent thrombosis. Antithrombin-III deficiency is classified into 4 types. Type I: characterized by a 50% decrease in antigenic and functional levels. Type II: has defects affecting the thrombin-binding domain. Type III: alteration of the heparin-binding domain. Plasma AT-III antigen levels are normal in type II and III. Type IV: consists of miscellaneous group of unclassifiable mutations. Note=The disease is caused by mutations affecting the gene represented in this entry.
The name and a short description of the disease associated with the variant. For more information about the disease, the user can refer to OMIM, following the link provided after the disease acronym.

Variant description:  In AT3D; type-I.
Any additional useful information about the variant.



Sequence information

Variant position:  121
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Protein sequence length:  464
The length of the canonical sequence.

Location on the sequence:   SKNDNDNIFLSPLSISTAFA  M TKLGACNDTLQQLMEVFKFD
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.

Human                         SKNDNDNIFLSPLSISTAFAMTKLGACNDTLQQLMEVFKFD

Mouse                         SKNDNDNIFLSPLSISTAFAMTKLGACNDTLKQLMEVFKFD

Bovine                        SKNNNDNIFLSPLSISTAFAMTKLGACNNTLKQLMEVFKFD

Sheep                         SKNNNDNIFLSPLSISTAFAMTKLGACNNTLKQLMEVFKFD

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.

TypePositionsDescription
Chain 33 – 464 Antithrombin-III
Glycosylation 128 – 128 N-linked (GlcNAc...)
Disulfide bond 40 – 160
Disulfide bond 53 – 127
Helix 112 – 123


Literature citations

Five novel and four recurrent point mutations in the antithrombin gene causing venous thrombosis.
Nagaizumi K.; Inaba H.; Amano K.; Suzuki M.; Arai M.; Fukutake K.;
Int. J. Hematol. 78:79-83(2003)
Cited for: VARIANTS AT3D LYS-121; HIS-178; CYS-425; HIS-425 AND PRO-441;

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.