Results

RDF/XMLNTriplesTurtleShow queryShare ▶
SubjectPredicateObject
http://purl.uniprot.org/citations/15987364http://www.w3.org/1999/02/22-rdf-syntax-ns#typehttp://purl.uniprot.org/core/Journal_Citation
http://purl.uniprot.org/citations/15987364http://www.w3.org/2000/01/rdf-schema#comment"

Background

Few studies have investigated the reaction kinetics and interactions with nucleotide donor and acceptor substrates of mutant human ABO glycosyltransferases. Previous work identified a B(w) allele featuring a 556G>A polymorphism giving rise to a weak B phenotype. This polymorphism is predicted to cause a M186V amino-acid mutation within a highly conserved series of 16 amino acids present both in both blood group A- and blood group B-synthesizing enzymes. These residues are known as the disordered loop because their location cannot be determined in the crystal structure of the enzyme. Another patient has been identified with a 556G>A B(w) allele and the kinetics of the resulting mutant glycosyltransferase were studied.

Study design and methods

Serologic testing with murine and human reagents, amplification of the coding regions of exons 6 and 7, and DNA sequencing were performed with standard protocols. Enzyme kinetic studies utilized a model of human GTB M186V expressed in Escherichia coli with radiolabeled UDP-galactose and UDP-N-acetylgalactosamine as donor substrates and synthetic H-disaccharide as acceptor following standard protocols.

Results

The patient's red blood cells demonstrated a weak, but not mixed-field, B phenotype. Kinetic studies on the mutant enzyme revealed diminished activity (k(cat) = 0.15 per sec with UDP-galactose compared to 5.1 per sec for wild-type GTB) and elevated K(m) values for all substrates.

Conclusion

This enzyme with a mutation in the disordered loop produces weak B antigen expression because of greatly decreased enzyme activity and reduced affinity for B-donor and acceptor substances."xsd:string
http://purl.uniprot.org/citations/15987364http://purl.org/dc/terms/identifier"doi:10.1111/j.1537-2995.2005.00170.x"xsd:string
http://purl.uniprot.org/citations/15987364http://purl.uniprot.org/core/author"Palcic M.M."xsd:string
http://purl.uniprot.org/citations/15987364http://purl.uniprot.org/core/author"Rose N.L."xsd:string
http://purl.uniprot.org/citations/15987364http://purl.uniprot.org/core/author"Denomme G.A."xsd:string
http://purl.uniprot.org/citations/15987364http://purl.uniprot.org/core/author"Yazer M.H."xsd:string
http://purl.uniprot.org/citations/15987364http://purl.uniprot.org/core/date"2005"xsd:gYear
http://purl.uniprot.org/citations/15987364http://purl.uniprot.org/core/name"Transfusion"xsd:string
http://purl.uniprot.org/citations/15987364http://purl.uniprot.org/core/pages"1178-1182"xsd:string
http://purl.uniprot.org/citations/15987364http://purl.uniprot.org/core/title"Amino-acid substitution in the disordered loop of blood group B-glycosyltransferase enzyme causes weak B phenotype."xsd:string
http://purl.uniprot.org/citations/15987364http://purl.uniprot.org/core/volume"45"xsd:string
http://purl.uniprot.org/citations/15987364http://www.w3.org/2004/02/skos/core#exactMatchhttp://purl.uniprot.org/pubmed/15987364
http://purl.uniprot.org/citations/15987364http://xmlns.com/foaf/0.1/primaryTopicOfhttps://pubmed.ncbi.nlm.nih.gov/15987364
http://purl.uniprot.org/uniprot/B0B1U2#attribution-BCEEF2759E668F5B44B6210D89E3021Ahttp://purl.uniprot.org/core/sourcehttp://purl.uniprot.org/citations/15987364
http://purl.uniprot.org/uniprot/#_A0A068B0Y9-mappedCitation-15987364http://www.w3.org/1999/02/22-rdf-syntax-ns#objecthttp://purl.uniprot.org/citations/15987364
http://purl.uniprot.org/uniprot/#_A0A089QDC1-mappedCitation-15987364http://www.w3.org/1999/02/22-rdf-syntax-ns#objecthttp://purl.uniprot.org/citations/15987364
http://purl.uniprot.org/uniprot/#_A0A0A7RCH0-mappedCitation-15987364http://www.w3.org/1999/02/22-rdf-syntax-ns#objecthttp://purl.uniprot.org/citations/15987364
http://purl.uniprot.org/uniprot/#_A0A0A8WK19-mappedCitation-15987364http://www.w3.org/1999/02/22-rdf-syntax-ns#objecthttp://purl.uniprot.org/citations/15987364
http://purl.uniprot.org/uniprot/#_A0A023J8Y7-mappedCitation-15987364http://www.w3.org/1999/02/22-rdf-syntax-ns#objecthttp://purl.uniprot.org/citations/15987364
http://purl.uniprot.org/uniprot/#_A0A0N7FMT7-mappedCitation-15987364http://www.w3.org/1999/02/22-rdf-syntax-ns#objecthttp://purl.uniprot.org/citations/15987364
http://purl.uniprot.org/uniprot/#_A0A060VD92-mappedCitation-15987364http://www.w3.org/1999/02/22-rdf-syntax-ns#objecthttp://purl.uniprot.org/citations/15987364
http://purl.uniprot.org/uniprot/#_A0A060VGH1-mappedCitation-15987364http://www.w3.org/1999/02/22-rdf-syntax-ns#objecthttp://purl.uniprot.org/citations/15987364
http://purl.uniprot.org/uniprot/#_A0A060VHY2-mappedCitation-15987364http://www.w3.org/1999/02/22-rdf-syntax-ns#objecthttp://purl.uniprot.org/citations/15987364
http://purl.uniprot.org/uniprot/#_A0A0D3RYQ2-mappedCitation-15987364http://www.w3.org/1999/02/22-rdf-syntax-ns#objecthttp://purl.uniprot.org/citations/15987364
▶