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UniProtKB/Swiss-Prot variant pages

UniProtKB/Swiss-Prot P02649: Variant p.Ala170Pro

Apolipoprotein E
Gene: APOE
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Variant information Variant position: help 170 The position of the amino-acid change on the UniProtKB canonical protein sequence.
Type of variant: help 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: help From Alanine (A) to Proline (P) at position 170 (A170P, p.Ala170Pro). 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: help Change from small size and hydrophobic (A) to medium size and hydrophobic (P) The physico-chemical property of the reference and variant residues and the change implicated.
BLOSUM score: help -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

Polymorphism: help There are three common APOE alleles identified: APOE*2/APOE-epsilon2/E2, APOE*3/APOE-epsilon3/E3, and APOE*4/APOE-epsilon4/E4. The corresponding ApoE2, ApoE3 and ApoE4 isoforms differentially present Cys and Arg residues at positions 130 and 176. The most common allele in the human population is APOE*3 which sequence is the one displayed in that entry with a Cys at position 130 and an Arg at position 176. Common APOE variants influence lipoprotein metabolism in healthy individuals. Additional variants have been described and are described relative to the three common alleles. Allele APOE*4 is strongly associated with risk for severe COVID-19, increases susceptibility to SARS-CoV-2 infection in neurons and astrocytes (PubMed:33450186). Additional information on the polymorphism described.
Variant description: help In ApoE3*; decreased binding to LDL receptor. Any additional useful information about the variant.
Other resources: help Links to websites of interest for the variant.


Sequence information Variant position: help 170 The position of the amino-acid change on the UniProtKB canonical protein sequence.
Protein sequence length: help 317 The length of the canonical sequence.
Location on the sequence: help ELRVRLASHLRKLRKRLLRD A DDLQKRLAVYQAGAREGAER 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: help The multiple alignment of the region surrounding the variant against various orthologous sequences.
Human                         ELRVRLASHLRKLRKRLLRDADDLQKRLAVYQAGAREGAER

Gorilla                       ELRARLASHLRKLRKRLLRDADDLQKRLAVYQAGAREGAER

                              ELRARFASHMRKLRKRVLRDAEDLQRRLAVYKAGVREGAER

Rhesus macaque                ELRARLASHLRKLRKRLLRDADDLQKRLA------------

Chimpanzee                    ELRARLASHLRKLRKRLLRDADDLQKRLAVYQAGAREGAER

Mouse                         EIRARLSTHLRKMRKRLMRDAEDLQKRLAVYKAGAREGAER

Rat                           ELRSRLSTHLRKMRKRLMRDADDLQKRLAVYKAGAQEGAER

Pig                           ELRSRLASHLRNVRKRLVRDTEDLQKRLAVYQAGLREGAER

Bovine                        ELRARMASHLRKLPKRLLRDADDLKKRLAVYQAGASEGAER

Rabbit                        ELARAFSSHLRKLRKRLLRDAEDLQKRMAVYGAGAREGAER

Sheep                         ELRARMASHLRKLRKRLLRDADDLKKRLAVYQAGASEGAER

Sequence annotation in neighborhood: help 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 19 – 317 Apolipoprotein E
Repeat 168 – 189 5
Region 80 – 255 8 X 22 AA approximate tandem repeats
Mutagenesis 157 – 157 S -> R. Increased binding to LDL receptor; when associated with A-167.
Mutagenesis 158 – 158 H -> A. Decreased binding to LDL receptor.
Mutagenesis 161 – 161 K -> A. Decreased binding to LDL receptor.
Mutagenesis 162 – 162 L -> P. Decreased binding to LDL receptor.
Mutagenesis 167 – 167 L -> A. Increased binding to LDL receptor; when associated with R-157.
Mutagenesis 168 – 168 R -> A. Decreased binding to LDL receptor.
Mutagenesis 172 – 172 D -> A. Restores the LDL receptor binding activity of ApoE2.
Helix 149 – 180



Literature citations
Human apolipoprotein E mRNA. cDNA cloning and nucleotide sequencing of a new variant.
McLean J.W.; Elshourbagy N.A.; Chang D.J.; Mahley R.W.; Taylor J.M.;
J. Biol. Chem. 259:6498-6504(1984)
Cited for: NUCLEOTIDE SEQUENCE [MRNA]; VARIANTS THR-117 AND PRO-170; Site-specific mutagenesis of human apolipoprotein E. Receptor binding activity of variants with single amino acid substitutions.
Lalazar A.; Weisgraber K.H.; Rall S.C. Jr.; Giladi H.; Innerarity T.L.; Levanon A.Z.; Boyles J.K.; Amit B.; Gorecki M.; Mahley R.W.;
J. Biol. Chem. 263:3542-3545(1988)
Cited for: CHARACTERIZATION OF VARIANTS SER-154 AND PRO-170; MUTAGENESIS OF SER-157; HIS-158; LYS-161; LEU-162; LEU-167 AND ARG-168;
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.