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UniProtKB/Swiss-Prot variant pages

UniProtKB/Swiss-Prot Q09470: Variant p.Asn255Asp

Potassium voltage-gated channel subfamily A member 1
Gene: KCNA1
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Variant information Variant position: help 255 The position of the amino-acid change on the UniProtKB canonical protein sequence.
Type of variant: help 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: help From Asparagine (N) to Aspartate (D) at position 255 (N255D, p.Asn255Asp). 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 medium size and polar (N) to medium size and acidic (D) 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

Variant description: help In MK1; strongly reduces the activity of homomeric channels with dominant negative effects on wild-type channels. Any additional useful information about the variant.
Other resources: help Links to websites of interest for the variant.


Sequence information Variant position: help 255 The position of the amino-acid change on the UniProtKB canonical protein sequence.
Protein sequence length: help 495 The length of the canonical sequence.
Location on the sequence: help ELVVRFFACPSKTDFFKNIM N FIDIVAIIPYFITLGTEIAE 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                         ELVVRFFACPSKTDFFKNIMNFIDIVAIIPYFITLGTEIAE

Mouse                         ELVVRFFACPSKTDFFKNIMNFIDIVAIIPYFITLGTEIAE

Rat                           ELVVRFFACPSKTDFFKNIMNFIDIVAIIPYFITLGTEIAE

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 1 – 495 Potassium voltage-gated channel subfamily A member 1
Transmembrane 254 – 274 Helical; Name=Segment S3
Lipidation 243 – 243 S-palmitoyl cysteine
Mutagenesis 243 – 243 C -> A. Strongly decreases palmitoylation and alters current kinetics.
Mutagenesis 255 – 255 N -> AHT. Slightly increases channel activity, but does not affect expression at the cell membrane.
Mutagenesis 255 – 255 N -> E. Abolishes channel activity, but does not affect expression at the cell membrane.
Mutagenesis 255 – 255 N -> Q. Strongly reduces channel activity, but does not affect expression at the cell membrane.
Mutagenesis 255 – 255 N -> V. No effect on channel activity.



Literature citations
A missense mutation in the Kv1.1 voltage-gated potassium channel-encoding gene KCNA1 is linked to human autosomal dominant hypomagnesemia.
Glaudemans B.; van der Wijst J.; Scola R.H.; Lorenzoni P.J.; Heister A.; van der Kemp A.W.; Knoers N.V.; Hoenderop J.G.; Bindels R.J.;
J. Clin. Invest. 119:936-942(2009)
Cited for: VARIANT MK1 ASP-255; CHARACTERIZATION OF VARIANT MK1 ASP-255; FUNCTION; TRANSPORTER ACTIVITY; SUBCELLULAR LOCATION; ACTIVITY REGULATION; Functional analysis of the Kv1.1 N255D mutation associated with autosomal dominant hypomagnesemia.
van der Wijst J.; Glaudemans B.; Venselaar H.; Nair A.V.; Forst A.L.; Hoenderop J.G.; Bindels R.J.;
J. Biol. Chem. 285:171-178(2010)
Cited for: CHARACTERIZATION OF VARIANT MK1 ASP-255; MUTAGENESIS OF ASN-255; FUNCTION; TRANSPORTER ACTIVITY; SUBCELLULAR LOCATION;
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.