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UniProtKB/Swiss-Prot P13716: Variant p.Arg240Trp

Delta-aminolevulinic acid dehydratase
Gene: ALAD
Variant information

Variant position:  240
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 Arginine (R) to Tryptophan (W) at position 240 (R240W, p.Arg240Trp).
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 large size and basic (R) to large size and aromatic (W)
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

Variant description:  In AHEPP; mixture of about 80% hexamer and 20% octamer; about 4% residual activity.
Any additional useful information about the variant.

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



Sequence information

Variant position:  240
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Protein sequence length:  330
The length of the canonical sequence.

Location on the sequence:   DRRCYQLPPGARGLALRAVD  R DVREGADMLMVKPGMPYLDI
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.

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 – 330 Delta-aminolevulinic acid dehydratase
Active site 252 – 252 Schiff-base intermediate with substrate
Metal binding 223 – 223 Zinc 2
Binding site 221 – 221 Substrate 1
Modified residue 252 – 252 N6-succinyllysine
Mutagenesis 223 – 223 C -> A. No effect on catalytic activity; when associated with A-131.
Helix 231 – 243


Literature citations

Cloning and expression of the defective genes from a patient with delta-aminolevulinate dehydratase porphyria.
Ishida N.; Fujita H.; Fukuda Y.; Noguchi T.; Doss M.; Kappas A.; Sassa S.;
J. Clin. Invest. 89:1431-1437(1992)
Cited for: NUCLEOTIDE SEQUENCE [MRNA] (ISOFORM 1); VARIANTS AHEPP TRP-240 AND THR-274;

Cloning and expression of the defective genes in delta-aminolevulinate dehydratase porphyria: compound heterozygosity in this hereditary liver disease.
Sassa S.; Ishida N.; Fujita H.; Fukuda Y.; Noguchi T.; Doss M.; Kappas A.;
Trans. Assoc. Am. Physicians 105:250-259(1992)
Cited for: VARIANTS AHEPP TRP-240 AND THR-274; CHARACTERIZATION OF VARIANTS AHEPP TRP-240 AND THR-274;

ALAD porphyria is a conformational disease.
Jaffe E.K.; Stith L.;
Am. J. Hum. Genet. 80:329-337(2007)
Cited for: CHARACTERIZATION OF VARIANTS AHEPP ARG-133; MET-153; TRP-240; THR-274 AND MET-275; CHARACTERIZATION OF VARIANTS LEU-12 AND ASN-59;

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.