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UniProtKB/Swiss-Prot variant pages

UniProtKB/Swiss-Prot P51787: Variant p.Ala344Val

Potassium voltage-gated channel subfamily KQT member 1
Gene: KCNQ1
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Variant information Variant position: help 344 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 Alanine (A) to Valine (V) at position 344 (A344V, p.Ala344Val). 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 (V) The physico-chemical property of the reference and variant residues and the change implicated.
BLOSUM score: help 0 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 LQT1. Any additional useful information about the variant.
Other resources: help Links to websites of interest for the variant.


Sequence information Variant position: help 344 The position of the amino-acid change on the UniProtKB canonical protein sequence.
Protein sequence length: help 676 The length of the canonical sequence.
Location on the sequence: help VGKTIASCFSVFAISFFALP A GILGSGFALKVQQKQRQKHF 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                         VGKTIASCFSVFAISFFALPAGILGSGFALKVQQKQRQKHF

Mouse                         VGKTIASCFSVFAISFFALPAGILGSGFALKVQQKQRQKHF

Rat                           VGKTIASCFSVFAISFFALPAGILGSGFALKVQQKQRQKHF

Pig                           VGKTIASCFSVFAISFFALPAGILGSGFALKVQQKQRQKHF

Rabbit                        VGKTIASCFSVFAISFFALPAGILGSGFALKVQQKQRQKHF

Xenopus laevis                IGKTIASCFSVFAISFFALPAGILGSGFALKVQQKQRQKHF
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 – 676 Potassium voltage-gated channel subfamily KQT member 1
Transmembrane 328 – 348 Helical; Name=Segment S6
Mutagenesis 324 – 324 V -> L. Has a voltage-gated potassium channel activity. Inhibition of voltage-gated potassium channel activity by KCNE4.
Mutagenesis 326 – 326 K -> R. Has a voltage-gated potassium channel activity. Disrupts KCNE4-mediated voltage-gated potassium channel activity inhibition.
Mutagenesis 327 – 327 T -> V. Has a voltage-gated potassium channel activity. Disrupts KCNE4-mediated voltage-gated potassium channel activity inhibition.
Mutagenesis 328 – 328 I -> L. Has a voltage-gated potassium channel activity. Inhibition of voltage-gated potassium channel activity by KCNE4.
Mutagenesis 338 – 338 S -> C. Inhibits voltage-gated potassium channel activity.
Mutagenesis 340 – 340 F -> C. Inhibits voltage-gated potassium channel activity.
Helix 342 – 360



Literature citations
KVLQT1 C-terminal missense mutation causes a forme fruste long-QT syndrome.
Donger C.; Denjoy I.; Berthet M.; Neyroud N.; Cruaud C.; Bennaceur M.; Chivoret G.; Schwartz K.; Coumel P.; Guicheney P.;
Circulation 96:2778-2781(1997)
Cited for: VARIANTS LQT1 ARG-168; CYS-174; GLN-190; MET-254; LYS-261; ASP-269; ARG-309; SER-314; SER-315; ALA-320; ARG-325; VAL-341; PHE-342; VAL-344; THR-371 AND CYS-555; Compendium of cardiac channel mutations in 541 consecutive unrelated patients referred for long QT syndrome genetic testing.
Tester D.J.; Will M.L.; Haglund C.M.; Ackerman M.J.;
Heart Rhythm 2:507-517(2005)
Cited for: VARIANTS LQT1 71-ALA--PRO-73 DEL; THR-73; GLY-115; TYR-122; ILE-133; PHE-136; LYS-160; ARG-168; CYS-174; GLN-190; PHE-204; LEU-225; ASN-235; ASN-242; CYS-243; MET-254; 254-VAL--PHE-256 DEL; CYS-259; LEU-259; ASP-261; PRO-266; SER-269; ASP-269; PHE-273; ARG-273; SER-276 DEL; LEU-277; HIS-278; LYS-290; ASP-292; CYS-293; VAL-302; ARG-304; SER-305; ILE-312; SER-314; ARG-314; ASP-314; CYS-315; ARG-316; ALA-322; PHE-339 DEL; VAL-341; SER-343; GLU-344; VAL-344; GLU-345; TRP-349; PRO-353; ARG-362; TRP-366; HIS-374; SER-380; TYR-389; TRP-452; GLY-524; GLU-526; TRP-539; LEU-546; CYS-555; HIS-555; TYR-566; SER-567; ARG-568; MET-587; THR-590; HIS-591; GLN-594; MET-619 AND SER-626; Spectrum of pathogenic mutations and associated polymorphisms in a cohort of 44 unrelated patients with long QT syndrome.
Millat G.; Chevalier P.; Restier-Miron L.; Da Costa A.; Bouvagnet P.; Kugener B.; Fayol L.; Gonzalez Armengod C.; Oddou B.; Chanavat V.; Froidefond E.; Perraudin R.; Rousson R.; Rodriguez-Lafrasse C.;
Clin. Genet. 70:214-227(2006)
Cited for: VARIANTS LQT1 CYS-231; PRO-243; CYS-259; HIS-259; PHE-273; SER-314; GLU-316; VAL-341; VAL-344 AND SER-626;
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.