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UniProtKB/Swiss-Prot variant pages

UniProtKB/Swiss-Prot P35520: Variant p.Arg266Lys

Cystathionine beta-synthase
Gene: CBS
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Variant information Variant position: help 266 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 Lysine (K) at position 266 (R266K, p.Arg266Lys). 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 Similar physico-chemical property. Both residues are large size and basic. The physico-chemical property of the reference and variant residues and the change implicated.
BLOSUM score: help 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
Variant description: help In CBSD; mild form; decreased cystathionine beta-synthase activity; decreased homotetramer formation; no effect on heme-binding; decreased stability. Any additional useful information about the variant.
Other resources: help Links to websites of interest for the variant.


Sequence information Variant position: help 266 The position of the amino-acid change on the UniProtKB canonical protein sequence.
Protein sequence length: help 551 The length of the canonical sequence.
Location on the sequence: help GKLDMLVASVGTGGTITGIA R KLKEKCPGCRIIGVDPEGSI 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                         GKLDMLVASVGTGGTITGIARKLKEKCPGCRIIGVDPEGSI

Mouse                         GKLDMLVASAGTGGTITGIARKLKEKCPGCKIIGVDPEGSI

Rat                           GKVDMLVASAGTGGTITGIARKLKEKCPGCKIIGVDPEGSI

Rabbit                        GKLDMLVASAGTGGTITGIARKLKEKCPGCQIIGVDPEGSI

Slime mold                    GKIDMIVCTAGTGGTITGIARKIKERLPNCIVVGVDPHGSI

Baker's yeast                 DNLRAVVAGAGTGGTISGISKYLKEQNDKIQIVGADPFGSI
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 1 – 551 Cystathionine beta-synthase
Mutagenesis 272 – 272 C -> A. Reduced heme content and cystathionine beta-synthase activity.
Mutagenesis 275 – 275 C -> S. Reduced heme content and cystathionine beta-synthase activity.
Helix 259 – 271



Literature citations
Cystathionine beta-synthase mutations: effect of mutation topology on folding and activity.
Kozich V.; Sokolova J.; Klatovska V.; Krijt J.; Janosik M.; Jelinek K.; Kraus J.P.;
Hum. Mutat. 31:809-819(2010)
Cited for: CHARACTERIZATION OF VARIANTS CBSD LEU-49; ARG-65; ARG-78; ASN-102; VAL-114; GLN-125; LYS-144; ARG-148; TYR-165; LYS-176; ALA-180; MET-191; LYS-228; ARG-262; LYS-266; THR-278; LYS-302; ARG-305; SER-307; CYS-369; LEU-422; THR-435; GLN-439; ASN-444; LEU-466 AND SER-539; FUNCTION; CATALYTIC ACTIVITY; PATHWAY; ACTIVITY REGULATION; SUBUNIT; Functional modeling of vitamin responsiveness in yeast: a common pyridoxine-responsive cystathionine beta-synthase mutation in homocystinuria.
Kim C.E.; Gallagher P.M.; Guttormsen A.B.; Refsum H.; Ueland P.M.; Ose L.; Foelling I.; Whitehead A.S.; Tsai M.Y.; Kruger W.D.;
Hum. Mol. Genet. 6:2213-2221(1997)
Cited for: VARIANTS CBSD MET-262; LYS-266; THR-278; SER-307; ALA-320 AND CYS-369; Effect of the disease-causing R266K mutation on the heme and PLP environments of human cystathionine beta-synthase.
Smith A.T.; Su Y.; Stevens D.J.; Majtan T.; Kraus J.P.; Burstyn J.N.;
Biochemistry 51:6360-6370(2012)
Cited for: VARIANT CBSD LYS-266; CHARACTERIZATION OF VARIANT CBSD LYS-266; ACTIVITY REGULATION;
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.