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UniProtKB/Swiss-Prot P0C0L4: Variant p.Val1207Ala

Complement C4-A
Gene: C4A
Variant information

Variant position:  1207
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Type of variant:  Polymorphism
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 Valine (V) to Alanine (A) at position 1207 (V1207A, p.Val1207Ala).
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 medium size and hydrophobic (V) to small size and hydrophobic (A)
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

Polymorphism:  The complement component C4 is the most polymorphic protein of the complement system. It is the product of 2 closely linked and highly homologous genes, C4A and C4B. Once polymorphic variation is discounted, the 2 isotypes differ by only 4 amino acids at positions 1120-1125: PCPVLD for C4A and LSPVIH for C4B. The 2 isotypes bear several antigenic determinants defining Chido/Rodgers blood group system [MIM:614374]. Rodgers determinants are generally associated with C4A allotypes, and Chido with C4B. Variations at these loci involve not only nucleotide polymorphisms, but also gene number and gene size. Some individuals may lack either C4A, or C4B gene. Partial deficiency of C4A or C4B is the most commonly inherited immune deficiency known in humans with a combined frequency over 31% in the normal Caucasian population (PubMed:11367523). C4A6 allotype is deficient in hemolytic activity. Allotype C4A13 is infrequent. Common copy-number variants of C4A and C4B affecting expression of complement component C4 in the brain have been associated with schizophrenia risk (PubMed:26814963).
Additional information on the polymorphism described.

Variant description:  In allotype C4A1, allotype C4A13.
Any additional useful information about the variant.

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



Sequence information

Variant position:  1207
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Protein sequence length:  1744
The length of the canonical sequence.

Location on the sequence:   LLGAHAAAITAYALTLTKAP  V DLLGVAHNNLMAMAQETGDN
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 680 – 1446 Complement C4-A alpha chain
Chain 757 – 1446 C4b-A
Chain 957 – 1336 C4d-A
Helix 1207 – 1218


Literature citations

Molecular genetics of complement C4: implications for MHC evolution and disease susceptibility gene mapping.
Sayer D.; Puschendorf M.; Wetherall J.;
Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA] OF 448-570 AND 692-1225; VARIANTS TRP-477; PRO-549; THR-907; GLY-1073; SER-1176; ALA-1207 AND ARG-1210;

The chemical structure of the C4d fragment of the human complement component C4.
Chakravarti D.N.; Campbell R.D.; Porter R.R.;
Mol. Immunol. 24:1187-1197(1987)
Cited for: PROTEIN SEQUENCE OF 957-1336; VARIANTS GLY-1073; SER-1176; ALA-1207; ARG-1210 AND ALA-1286;

Amino acid sequence of a polymorphic segment from fragment C4d of human complement component C4.
Chakravarti D.N.; Campbell R.D.; Gagnon J.;
FEBS Lett. 154:387-390(1983)
Cited for: PROTEIN SEQUENCE OF 1199-1304; VARIANTS ALA-1207; ARG-1210 AND ALA-1286;

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.