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UniProtKB/Swiss-Prot variant pages

UniProtKB/Swiss-Prot P0C0L5: Variant p.Ile1317Phe

Complement C4-B
Gene: C4B_2
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Variant information Variant position: help 1317 The position of the amino-acid change on the UniProtKB canonical protein sequence.
Type of variant: help LB/B 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 Isoleucine (I) to Phenylalanine (F) at position 1317 (I1317F, p.Ile1317Phe). 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 medium size and hydrophobic (I) to large size and aromatic (F) The physico-chemical property of the reference and variant residues and the change implicated.
BLOSUM score: help 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: help 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. The second copy of C4B gene present in some individuals has been called C4B_2 by the HUGO Gene Nomenclature Committee (HGNC). 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). 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: help In allotype C4B1-SC01. Any additional useful information about the variant.
Other resources: help Links to websites of interest for the variant.


Sequence information Variant position: help 1317 The position of the amino-acid change on the UniProtKB canonical protein sequence.
Protein sequence length: help 1744 The length of the canonical sequence.
Location on the sequence: help GGFRSTQDTVIALDALSAYW I ASHTTEERGLNVTLSSTGRN 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                         GGFRSTQDTVIALDALSAYWIASHTTEERGLNVTLSSTGRN

Mouse                         GAFRSTQDTVVTLDALSAYWIASHTTEEKALNVTLSSMGRN

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 680 – 1446 Complement C4-B alpha chain
Chain 757 – 1446 C4b-B
Chain 957 – 1336 C4d-B
Glycosylation 1328 – 1328 N-linked (GlcNAc...) asparagine



Literature citations
Complete sequence of the complement C4 gene from the HLA-A1, B8, C4AQ0, C4B1, DR3 haplotype.
Ulgiati D.; Townend D.C.; Christiansen F.T.; Dawkins R.L.; Abraham L.J.;
Immunogenetics 43:250-252(1996)
Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA]; VARIANT PHE-1317;
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.