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UniProtKB/Swiss-Prot Q9Y6H8: Variant p.Arg76Gly

Gap junction alpha-3 protein
Gene: GJA3
Variant information

Variant position:  76
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Type of variant:  Disease [Disclaimer]
The variants are classified into three categories: Disease, Polymorphism and Unclassified.
  • Disease: Variants implicated in disease according to literature reports.
  • Polymorphism: Variants not reported to be implicated in disease.
  • Unclassified: Variants with uncertain implication in disease according to literature reports. Evidence against or in favor of a pathogenic role is limited and/or conflicting.

Residue change:  From Arginine (R) to Glycine (G) at position 76 (R76G, p.Arg76Gly).
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 basic (R) to glycine (G)
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

Involvement in disease:  Cataract 14, multiple types (CTRCT14) [MIM:601885]: An opacification of the crystalline lens of the eye that frequently results in visual impairment or blindness. Opacities vary in morphology, are often confined to a portion of the lens, and may be static or progressive. CTRCT14 includes zonular pulverulent cataract, among others. Zonular or lamellar cataracts are opacities, broad or narrow, usually consisting of powdery white dots affecting only certain layers or zones between the cortex and nucleus of an otherwise clear lens. The opacity may be so dense as to render the entire central region of the lens completely opaque, or so translucent that vision is hardly if at all impeded. Usually sharply separated from a clear cortex outside them, they may have projections from their outer edges known as riders or spokes. {ECO:0000269|PubMed:10205266, ECO:0000269|PubMed:10746562, ECO:0000269|PubMed:14627959, ECO:0000269|PubMed:15208569, ECO:0000269|PubMed:15286166, ECO:0000269|PubMed:15448617, ECO:0000269|PubMed:16234473, ECO:0000269|PubMed:16254549, ECO:0000269|PubMed:16885921, ECO:0000269|PubMed:16971895, ECO:0000269|PubMed:17615540, ECO:0000269|PubMed:17893674, ECO:0000269|PubMed:20431721, ECO:0000269|PubMed:21552498, ECO:0000269|PubMed:21647269, ECO:0000269|PubMed:21681855, ECO:0000269|PubMed:21897748, ECO:0000269|PubMed:22312188, ECO:0000269|PubMed:24772942, ECO:0000269|PubMed:25635993, ECO:0000269|PubMed:26683566, ECO:0000269|PubMed:30044662}. Note=The disease is caused by mutations affecting the gene represented in this entry.
The name and a short description of the disease associated with the variant. For more information about the disease, the user can refer to OMIM, following the link provided after the disease acronym.

Variant description:  In CTRCT14; nearly abolishes formation of gap junctions; no significant effect on formation of functional hemichannels.
Any additional useful information about the variant.

Sequence information

Variant position:  76
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Protein sequence length:  435
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 2 – 435 Gap junction alpha-3 protein
Transmembrane 72 – 92 Helical
Disulfide bond 54 – 192
Disulfide bond 61 – 186
Disulfide bond 65 – 181
Mutagenesis 76 – 76 R -> EK. Abolishes formation of gap junctions. No significant effect on formation of functional hemichannels.

Literature citations

Novel mutations in GJA3 associated with autosomal dominant congenital cataract in the Indian population.
Devi R.R.; Reena C.; Vijayalakshmi P.;
Mol. Vis. 11:846-852(2005)
Cited for: VARIANTS CTRCT14 MET-28 AND GLY-76;

Alterations at Arg76 of human connexin 46, a residue associated with cataract formation, cause loss of gap junction formation but preserve hemichannel function.
Abrams C.K.; Peinado A.; Mahmoud R.; Bocarsly M.; Zhang H.; Chang P.; Botello-Smith W.M.; Freidin M.M.; Luo Y.;
Am. J. Physiol. 5:C623-C635(2018)

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.