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UniProtKB/Swiss-Prot variant pages

UniProtKB/Swiss-Prot P07686: Variant p.Arg505Gln

Beta-hexosaminidase subunit beta
Gene: HEXB
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Variant information Variant position: help 505 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 Arginine (R) to Glutamine (Q) at position 505 (R505Q, p.Arg505Gln). 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 basic (R) to medium size and polar (Q) 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 GM2G2. Any additional useful information about the variant.
Other resources: help Links to websites of interest for the variant.


Sequence information Variant position: help 505 The position of the amino-acid change on the UniProtKB canonical protein sequence.
Protein sequence length: help 556 The length of the canonical sequence.
Location on the sequence: help EACLWGEYVDATNLTPRLWP R ASAVGERLWSSKDVRDMDDA 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                         EACLWGEYVDATNLTPRLWPRASAVGERLWSSKDVRDMDDA

Mouse                         EACLWGEFVDATNLTPRLWPRASAVGERLWSPKTVTDLENA

Rat                           EACLWGEYVDATNLIPRLWPRASAVGERLWSPRIITNLENA

Pig                           EACLWGEYVDATNLTPRLWPRASAVGERLWSHKDVRDIHDA

Cat                           EACLWGEFVDATNLTPRLWPRASAVGERLWSPEDITSVGNA
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 122 – 556 Beta-hexosaminidase subunit beta
Chain 315 – 556 Beta-hexosaminidase subunit beta chain A
Site 497 – 497 Not glycosylated
Mutagenesis 491 – 491 E -> Q. No effect on substrate affinity and on catalytic efficiency.
Helix 505 – 514



Literature citations
Molecular basis of an adult form of Sandhoff disease: substitution of glutamine for arginine at position 505 of the beta-chain of beta-hexosaminidase results in a labile enzyme.
Bolhuis P.A.; Ponne N.J.; Bikker H.; Baas F.; Vianney de Jong J.M.B.;
Biochim. Biophys. Acta 1182:142-146(1993)
Cited for: VARIANT GM2G2 GLN-505; Significance of two point mutations present in each HEXB allele of patients with adult GM2 gangliosidosis (Sandhoff disease) homozygosity for the Ile207-->Val substitution is not associated with a clinical or biochemical phenotype.
Redonnet-Vernhet I.; Mahuran D.J.; Salvayre R.; Dubas F.; Levade T.;
Biochim. Biophys. Acta 1317:127-133(1996)
Cited for: VARIANT GM2G2 GLN-505; VARIANT VAL-207;
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.