Home  |  Contact

UniProtKB/Swiss-Prot P35520: Variant p.Leu540Gln

Cystathionine beta-synthase
Gene: CBS
Variant information

Variant position:  540
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 Leucine (L) to Glutamine (Q) at position 540 (L540Q, p.Leu540Gln).
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 (L) to medium size and polar (Q)
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

Variant description:  In CBSD; no effect on cystathionine beta-synthase activity; altered stimulation by AdoMet.
Any additional useful information about the variant.



Sequence information

Variant position:  540
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Protein sequence length:  551
The length of the canonical sequence.

Location on the sequence:   STGKSSQRQMVFGVVTAIDL  L NFVAAQERDQK
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.

Human                         STGKSSQRQMVFGVVTAIDLLNFVAAQERDQK

Mouse                         SNGMSSKQQMVFGVVTAIDLLNFVAAREQTQT

Rat                           NNGVSSKQLMVFGVVTAIDLLNFVAAREQTRK

Rabbit                        GDEQPSKRQTVFGVVTAMDLLHFVASRGQDQQ

Slime mold                    -----TENDEIISIVTKIDLLTYLMKSQQKN-

Baker's yeast                 -----TDGLKPIHIVTKMDLLSYLA-------

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 1 – 551 Cystathionine beta-synthase
Helix 536 – 544


Literature citations

Insights into the regulatory domain of cystathionine Beta-synthase: characterization of six variant proteins.
Mendes M.I.; Santos A.S.; Smith D.E.; Lino P.R.; Colaco H.G.; de Almeida I.T.; Vicente J.B.; Salomons G.S.; Rivera I.; Blom H.J.; Leandro P.;
Hum. Mutat. 35:1195-1202(2014)
Cited for: VARIANT CBSD GLY-449; CHARACTERIZATION OF VARIANTS CBSD LEU-427; ASN-444; GLY-449; LEU-500 AND GLN-540; CATALYTIC ACTIVITY;

Reduced response of Cystathionine Beta-Synthase (CBS) to S-Adenosylmethionine (SAM): Identification and functional analysis of CBS gene mutations in Homocystinuria patients.
Mendes M.I.; Colaco H.G.; Smith D.E.; Ramos R.J.; Pop A.; van Dooren S.J.; Tavares de Almeida I.; Kluijtmans L.A.; Janssen M.C.; Rivera I.; Salomons G.S.; Leandro P.; Blom H.J.;
J. Inherit. Metab. Dis. 37:245-254(2014)
Cited for: VARIANTS CBSD LEU-49; LYS-269 DEL; THR-278; HIS-336; LEU-427; ASN-444; LEU-500 AND GLN-540; CHARACTERIZATION OF VARIANTS CBSD LEU-49; LYS-269 DEL; THR-278; HIS-336; LEU-427; ASN-444; LEU-500 AND GLN-540; FUNCTION; CATALYTIC ACTIVITY; PATHWAY; 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.