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UniProtKB/Swiss-Prot Q9UHI7: Variant p.Ser421Ala

Solute carrier family 23 member 1
Gene: SLC23A1
Variant information

Variant position:  421
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 Serine (S) to Alanine (A) at position 421 (S421A, p.Ser421Ala).
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 small size and polar (S) to small size and hydrophobic (A)
The physico-chemical property of the reference and variant residues and the change implicated.

BLOSUM score:  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

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



Sequence information

Variant position:  421
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Protein sequence length:  598
The length of the canonical sequence.

Location on the sequence:   QYGAAIMLVLGTIGKFTALF  S SLPDPILGGMFCTLFGMITA
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                         QYGAAIMLVLGTIGKFTALFSSLPDPILGGMFCTLFGMITA

Mouse                         QYGAGIMLILGAIGKFTALFASLPDPILGGMFCTLFGMITA

Rat                           QYGAGIMLILGAIGKFTALFASLPDPILGGMFCTLFGMITA

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 – 598 Solute carrier family 23 member 1
Transmembrane 403 – 423 Helical
Alternative sequence 92 – 430 Missing. In isoform 3.


Literature citations

Molecular characterization of two novel transporters from human and mouse kidney and from LLC-PK1 cells reveals a novel conserved family that is homologous to bacterial and Aspergillus nucleobase transporters.
Faaland C.A.; Race J.E.; Ricken G.; Warner F.J.; Williams W.J.; Holtzman E.J.;
Biochim. Biophys. Acta 1442:353-360(1998)
Cited for: NUCLEOTIDE SEQUENCE [MRNA] (ISOFORM 1); VARIANT ALA-421;

Human Na(+)-dependent vitamin C transporter 1 (hSVCT1): primary structure, functional characteristics and evidence for a non-functional splice variant.
Wang H.; Dutta B.; Huang W.; Devoe L.D.; Leibach F.H.; Ganapathy V.; Prasad P.D.;
Biochim. Biophys. Acta 1461:1-9(1999)
Cited for: NUCLEOTIDE SEQUENCE [MRNA] (ISOFORMS 1 AND 2); VARIANT ALA-421;

Cloning and functional characterization of the human sodium-dependent vitamin C transporters hSVCT1 and hSVCT2.
Daruwala R.C.; Song J.; Koh W.S.; Rumsey S.C.; Levine M.;
FEBS Lett. 460:480-484(1999)
Cited for: NUCLEOTIDE SEQUENCE [MRNA] (ISOFORM 1); VARIANT ALA-421;

Human vitamin C (L-ascorbic acid) transporter SVCT1.
Wang Y.; Mackenzie B.; Tsukaguchi H.; Weremowicz S.; Morton C.C.; Hediger M.A.;
Biochem. Biophys. Res. Commun. 267:488-494(2000)
Cited for: NUCLEOTIDE SEQUENCE [MRNA] (ISOFORM 1); VARIANT ALA-421;

Characterization of the genomic structure of the human vitamin C transporter SVCT1 (SLC23A2).
Erichsen H.C.; Eck P.; Levine M.; Chanock S.;
J. Nutr. 131:2623-2627(2001)
Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA] (ISOFORM 1); VARIANT ALA-421;

Vitamin C transport systems of mammalian cells.
Liang W.J.; Johnson D.; Jarvis S.M.;
Mol. Membr. Biol. 18:87-95(2001)
Cited for: NUCLEOTIDE SEQUENCE [MRNA] (ISOFORM 1); VARIANT ALA-421;

The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC).
The MGC Project Team;
Genome Res. 14:2121-2127(2004)
Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA] (ISOFORMS 2 AND 3); VARIANT ALA-421;

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.