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UniProtKB/Swiss-Prot Q99250: Variant p.Phe928Cys

Sodium channel protein type 2 subunit alpha
Gene: SCN2A
Variant information

Variant position:  928
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Type of variant:  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:  From Phenylalanine (F) to Cysteine (C) at position 928 (F928C, p.Phe928Cys).
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 large size and aromatic (F) to medium size and polar (C)
The physico-chemical property of the reference and variant residues and the change implicated.

BLOSUM score:  -2
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:  In DEE11; mild form with ataxia.
Any additional useful information about the variant.

Sequence information

Variant position:  928
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Protein sequence length:  2005
The length of the canonical sequence.

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.




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.

Chain 1 – 2005 Sodium channel protein type 2 subunit alpha
Intramembrane 928 – 948 Pore-forming
Repeat 741 – 1013 II
Site 909 – 909 Binds SCN2B; via carbonyl oxygen
Site 916 – 916 Binds Mu-conotoxin KIIIA; via amide nitrogen
Site 920 – 920 Binds Mu-conotoxin KIIIA; via carbonyl oxygen
Site 945 – 945 Binds Mu-conotoxin KIIIA
Disulfide bond 910 – 910 Interchain; with SCN2B or SCN4B
Disulfide bond 910 – 910 Interchain; with the conotoxin GVIIJ (when the channel is not linked to SCN2B or SCN4B; the bond to SCN2B or SCN4B protects the channel from the inhibition by toxin)
Helix 928 – 938

Literature citations

Targeted resequencing in epileptic encephalopathies identifies de novo mutations in CHD2 and SYNGAP1.
Carvill G.L.; Heavin S.B.; Yendle S.C.; McMahon J.M.; O'Roak B.J.; Cook J.; Khan A.; Dorschner M.O.; Weaver M.; Calvert S.; Malone S.; Wallace G.; Stanley T.; Bye A.M.; Bleasel A.; Howell K.B.; Kivity S.; Mackay M.T.; Rodriguez-Casero V.; Webster R.; Korczyn A.; Afawi Z.; Zelnick N.; Lerman-Sagie T.; Lev D.; Moeller R.S.; Gill D.; Andrade D.M.; Freeman J.L.; Sadleir L.G.; Shendure J.; Berkovic S.F.; Scheffer I.E.; Mefford H.C.;
Nat. Genet. 45:825-830(2013)
Cited for: VARIANTS DEE11 ILE-136; ASN-905; CYS-928 AND GLN-1882;

SCN2A encephalopathy: A major cause of epilepsy of infancy with migrating focal seizures.
Howell K.B.; McMahon J.M.; Carvill G.L.; Tambunan D.; Mackay M.T.; Rodriguez-Casero V.; Webster R.; Clark D.; Freeman J.L.; Calvert S.; Olson H.E.; Mandelstam S.; Poduri A.; Mefford H.C.; Harvey A.S.; Scheffer I.E.;
Neurology 85:958-966(2015)
Cited for: VARIANTS DEE11 ILE-136; LYS-218; LEU-856; ASN-905; CYS-928; ARG-1593; VAL-1634 AND GLN-1882; VARIANT BFIS3 SER-240; VARIANT LYS-976;

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.