Expasy logo

UniProtKB/Swiss-Prot variant pages

UniProtKB/Swiss-Prot Q12809: Variant p.Phe640Leu

Potassium voltage-gated channel subfamily H member 2
Gene: KCNH2
Variant information Variant position: help 640 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 Phenylalanine (F) to Leucine (L) at position 640 (F640L, p.Phe640Leu). 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 large size and aromatic (F) to medium size and hydrophobic (L) 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 LQT2. Any additional useful information about the variant.
Other resources: help Links to websites of interest for the variant.

Sequence information Variant position: help 640 The position of the amino-acid change on the UniProtKB canonical protein sequence.
Protein sequence length: help 1159 The length of the canonical sequence.
Location on the sequence: help SSLTSVGFGNVSPNTNSEKI F SICVMLIGSLMYASIFGNVS 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.
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.
Chain 1 – 1159 Potassium voltage-gated channel subfamily H member 2
Transmembrane 639 – 659 Helical; Name=Segment S6
Mutagenesis 629 – 629 N -> Q. Abolishes cell surface expression; has no effect on N-glycosylation.
Mutagenesis 631 – 631 S -> A. No effect on cell surface expression, but changes inactivation kinetics; when associated with Q-598.

Literature citations
Novel KCNQ1 and HERG missense mutations in Dutch long-QT families.
Jongbloed R.J.E.; Wilde A.A.M.; Geelen J.L.M.C.; Doevendans P.; Schaap C.; van Langen I.; van Tintelen J.P.; Cobben J.M.; Beaufort-Krol G.C.M.; Geraedts J.P.M.; Smeets H.J.M.;
Hum. Mutat. 13:301-310(1999)
Cited for: VARIANTS LQT2 PRO-558; CYS-582; SER-604; MET-613 AND LEU-640;
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.