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UniProtKB/Swiss-Prot P16455: Variant p.Ile143Val

Methylated-DNA--protein-cysteine methyltransferase
Gene: MGMT
Variant information

Variant position:  143
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 Isoleucine (I) to Valine (V) at position 143 (I143V, p.Ile143Val).
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:  3
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

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



Sequence information

Variant position:  143
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Protein sequence length:  207
The length of the canonical sequence.

Location on the sequence:   NPKAARAVGGAMRGNPVPIL  I PCHRVVCSSGAVGNYSGGLA
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                         NPKAARAVGGAMRGNPVPILIPCHRVVCSSGAVGNYS-GGLA

                              NPKAARAVGGAMRSNPVPILIPCHRVVCSSGAMGNYT-GGL

Mouse                         NPKAARAVGGAMRSNPVPILIPCHRVVRSDGAIGHYSGGGQ

Rat                           NPKAARAVGGAMRSNPVPILIPCHRVIRSDGAIGNYSGGGQ

Baker's yeast                 KPTAARSVGRACGSNNLALLVPCHRIVGSNRKLTGYK-WSC

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 – 207 Methylated-DNA--protein-cysteine methyltransferase
Active site 145 – 145 Nucleophile; methyl group acceptor
Binding site 123 – 123 DNA
Binding site 128 – 128 DNA
Binding site 151 – 151 DNA; via amide nitrogen
Mutagenesis 128 – 128 R -> AD. Decreases activity towards methylated DNA over 1000-fold. No effect on reactivity with O6-benzylguanine.
Mutagenesis 128 – 128 R -> G. Loss of DNA repair activity.
Mutagenesis 128 – 128 R -> KL. Slightly reduced DNA repair activity.
Mutagenesis 138 – 138 P -> K. Decreased reactivity with O6-benzylguanine.
Mutagenesis 140 – 140 P -> A. Decreased reactivity with O6-benzylguanine.
Mutagenesis 145 – 145 C -> A. Loss of DNA repair activity.
Mutagenesis 156 – 156 G -> A. Decreased reactivity with O6-benzylguanine.
Mutagenesis 158 – 158 Y -> A. Reduced DNA repair activity. Decreased reactivity with O6-benzylguanine.
Mutagenesis 158 – 158 Y -> F. Slightly reduced DNA repair activity.


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.