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UniProtKB/Swiss-Prot P02708: Variant p.Phe276Leu

Acetylcholine receptor subunit alpha
Gene: CHRNA1
Variant information

Variant position:  276
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 Leucine (L) at position 276 (F276L, p.Phe276Leu).
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 hydrophobic (L)
The physico-chemical property of the reference and variant residues and the change implicated.

BLOSUM score:  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:  In CMS1B; fewer and shorter ion channel activations with decreased channel opening rate and increased channel closing rate.
Any additional useful information about the variant.

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



Sequence information

Variant position:  276
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Protein sequence length:  457
The length of the canonical sequence.

Location on the sequence:   PTDSGEKMTLSISVLLSLTV  F LLVIVELIPSTSSAVPLIGK
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:  
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 21 – 457 Acetylcholine receptor subunit alpha
Transmembrane 265 – 285 Helical
Mutagenesis 261 – 261 E -> Q. Changed acetylcholine-gated cation-selective channel activity.
Mutagenesis 275 – 275 V -> A. Increased length of channel opening.


Literature citations

Mutation in the AChR ion channel gate underlies a fast channel congenital myasthenic syndrome.
Webster R.; Brydson M.; Croxen R.; Newsom-Davis J.; Vincent A.; Beeson D.;
Neurology 62:1090-1096(2004)
Cited for: VARIANT CMS1B LEU-276; CHARACTERIZATION OF VARIANT CMS1B LEU-276;

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.