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UniProtKB/Swiss-Prot P04180: Variant p.Arg171Trp

Phosphatidylcholine-sterol acyltransferase
Gene: LCAT
Variant information

Variant position:  171
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 implicated in disease according to literature reports.
  • Polymorphism: Variants not reported to be implicated in disease.
  • Unclassified: Variants with uncertain implication in disease according to literature reports. Evidence against or in favor of a pathogenic role is limited and/or conflicting.

Residue change:  From Arginine (R) to Tryptophan (W) at position 171 (R171W, p.Arg171Trp).
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

Involvement in disease:  Lecithin-cholesterol acyltransferase deficiency (LCATD) [MIM:245900]: A disorder of lipoprotein metabolism characterized by inadequate esterification of plasmatic cholesterol. Two clinical forms are recognized: complete LCAT deficiency and fish-eye disease. LCATD is generally referred to the complete form which is associated with absence of both alpha and beta LCAT activities resulting in esterification anomalies involving both HDL (alpha-LCAT activity) and LDL (beta-LCAT activity). It causes a typical triad of diffuse corneal opacities, target cell hemolytic anemia, and proteinuria with renal failure. {ECO:0000269|PubMed:11423760, ECO:0000269|PubMed:12957688, ECO:0000269|PubMed:15994445, ECO:0000269|PubMed:16051254, ECO:0000269|PubMed:16216249, ECO:0000269|PubMed:1681161, ECO:0000269|PubMed:1859405, ECO:0000269|PubMed:2370048, ECO:0000269|PubMed:7607641, ECO:0000269|PubMed:7711728, ECO:0000269|PubMed:8318557, ECO:0000269|PubMed:8432868, ECO:0000269|PubMed:8807342, ECO:0000269|PubMed:9007616, ECO:0000269|PubMed:9741700}. 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 LCATD.
Any additional useful information about the variant.

Sequence information

Variant position:  171
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Protein sequence length:  440
The length of the canonical sequence.

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.





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.

Chain 25 – 440 Phosphatidylcholine-sterol acyltransferase
Site 173 – 173 Determinant for substrate specificity
Mutagenesis 173 – 173 E -> A. Increased activity towards PAPC. Increased PAPC/POPC activity ratio.
Mutagenesis 173 – 173 E -> D. Little change in enzyme specific activity nor in PAPC/POPC activity ratio.
Mutagenesis 173 – 173 E -> K. Decreased enzyme specific activity. Increased PAPC/POPC activity ratio.
Mutagenesis 173 – 173 E -> L. Increased activity towards PAPC. Increased PAPC/POPC activity ratio.
Mutagenesis 173 – 173 E -> Q. Decreased enzyme specific activity. Increased PAPC/POPC activity ratio.

Literature citations

Lecithin cholesterol acyl transferase deficiency: molecular analysis of a mutated allele.
Taramelli R.; Pontoglio M.; Candiani G.; Ottolenghi S.; Dieplinger H.; Catapano A.; Albers J.; Vergani C.; McLean J.;
Hum. Genet. 85:195-199(1990)
Cited for: VARIANT LCATD TRP-171;

The molecular basis of lecithin:cholesterol acyltransferase deficiency syndromes: a comprehensive study of molecular and biochemical findings in 13 unrelated Italian families.
Calabresi L.; Pisciotta L.; Costantin A.; Frigerio I.; Eberini I.; Alessandrini P.; Arca M.; Bon G.B.; Boscutti G.; Busnach G.; Frasca G.; Gesualdo L.; Gigante M.; Lupattelli G.; Montali A.; Pizzolitto S.; Rabbone I.; Rolleri M.; Ruotolo G.; Sampietro T.; Sessa A.; Vaudo G.; Cantafora A.; Veglia F.; Calandra S.; Bertolini S.; Franceschini G.;
Arterioscler. Thromb. Vasc. Biol. 25:1972-1978(2005)
Cited for: VARIANTS FED GLU-70 AND ALA-298; VARIANTS LCATD CYS-164; TRP-171; ASN-205; ASN-242; HIS-268; ILE-298 AND MET-333; VARIANTS PRO-115; THR-165 AND ARG-396;

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.