UniProtKB/Swiss-Prot P03905: Variant p.Thr109Ala

NADH-ubiquinone oxidoreductase chain 4
Gene: MT-ND4
Chromosomal location: M
Variant information

Variant position:  109
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 Threonine (T) to Alanine (A) at position 109 (T109A, p.Thr109Ala).
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 polar (T) to small size and hydrophobic (A)
The physico-chemical property of the reference and variant residues and the change implicated.

BLOSUM score:  0
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:  Mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes syndrome (MELAS) [MIM:540000]: Genetically heterogeneous disorder, characterized by episodic vomiting, seizures, and recurrent cerebral insults resembling strokes and causing hemiparesis, hemianopsia, or cortical blindness. 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 MELAS.
Any additional useful information about the variant.



Sequence information

Variant position:  109
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Protein sequence length:  459
The length of the canonical sequence.

Location on the sequence:   LSRKKLYLSMLISLQISLIM  T FTATELIMFYIFFETTLIPT
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                         LSRKKLYLSMLISLQISLIMTFTATELIMFYIFFETTLIPT

Gorilla                       LSRKKLYLSMLISLQISLIMTFTATELIMFYIFFEATLIPT

Chimpanzee                    LSRKKLYLSMLISLQISLIMTFSATELIMFYIFFETTLIPT

Mouse                         NVLQKLYISMLISLQILLIMTFSATELIMFYILFEATLIPT

Rat                           MMHQKLYISMLISLQILLIMTFSATELILFYILFEATLIPT

Pig                           TTRKKLYITMLILLQLFLIMTFTATELILFYILFEATLVPT

Bovine                        LTRKKLFITMLISLQLFLIMTFTAMELILFYILFEATLVPT

Rabbit                        LTRKKIYISLLISLQVFLVMTFSATEFILFYILFEATLIPT

Sheep                         LARKKLFISMLILLQLFLIMTFTATELIFFYIMFEATLVPT

Cat                           PSRKKLYITMLTLLQLLLIMTFTATELIMFYILFEATLIPT

Dog                           LTRKKLYISMLILLQLFLIMTFTASELIFFYILFEATLIPT

Horse                         LIRKKLYITMLTMLQTFLIMTFTATELISFYILFEATLVPT

Chicken                       HKRKRMFISTLIIIQPFIILAFSATELMLFYISFEATLIPT

Xenopus laevis                ISRQRTFITMLVFLQLSLIMAFSATELILFYIMFEITLIPT

Zebrafish                     VNRQRMYITLLASLQTFMIMAFGATKIIMFYIMFEATLIPT

Caenorhabditis elegans        --KNNNLLILSEILVFICIIFFIPSNMMMLYMFFELSMFPI

Drosophila                    NNYKNLFLLNIIILLLLLILTFSSMSLFMFYLFFESSLIPT

Slime mold                    --TEQKFQIMLLLTEILIINFFAATDLVQLYIVYEATLIPM

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 1 – 459 NADH-ubiquinone oxidoreductase chain 4
Transmembrane 102 – 122 Helical;


Literature citations

A new disease-related mutation for mitochondrial encephalopathy lactic acidosis and strokelike episodes (MELAS) syndrome affects the ND4 subunit of the respiratory complex I.
Lertrit P.; Noer A.S.; Jean-Francois M.J.B.; Kapsa R.; Dennett X.; Thyagarajan D.; Lethlean K.; Byrne E.; Marzuki S.;
Am. J. Hum. Genet. 51:457-468(1992)
Cited for: VARIANT MELAS ALA-109;

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.