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UniProtKB/Swiss-Prot O00142: Variant p.Met117Val

Thymidine kinase 2, mitochondrial
Gene: TK2
Variant information

Variant position:  117
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Type of variant:  LP/P [Disclaimer]
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 Methionine (M) to Valine (V) at position 117 (M117V, p.Met117Val).
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:  Similar physico-chemical property. Both residues are medium size and hydrophobic.
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

Variant description:  In MTDPS2; severe form of combined brain and muscular atrophy; depletion of mtDNA in skeletal muscle; normal residual mtDNA in blood and fibroblasts.
Any additional useful information about the variant.



Sequence information

Variant position:  117
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Protein sequence length:  265
The length of the canonical sequence.

Location on the sequence:   LMYHDASRWGLTLQTYVQLT  M LDRHTRPQVSSVRLMERSIH
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                         LMYHDASRWGLTLQTYVQLTMLDRHTRPQVSSVRLMERSIH

Mouse                         LMYHDASRWGLTLQTYVQLTMLDQHTRPQMSPVRLMERSIY

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 34 – 265 Thymidine kinase 2, mitochondrial
Active site 133 – 133 Proton acceptor
Binding site 99 – 99 Substrate
Binding site 110 – 110 Substrate
Binding site 134 – 134 Substrate


Literature citations

Clinical application of whole exome sequencing reveals a novel compound heterozygous TK2-mutation in two brothers with rapidly progressive combined muscle-brain atrophy, axonal neuropathy, and status epilepticus.
Knierim E.; Seelow D.; Gill E.; von Moers A.; Schuelke M.;
Mitochondrion 20:1-6(2015)
Cited for: VARIANTS MTDPS2 VAL-117 AND VAL-139;

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.