Amino acid substitutions at sugar-recognizing codons confer ABO blood group system-related α1,3 Gal(NAc) transferases with differential enzymatic activity
Cid, Emili (Institut Germans Trias i Pujol. Institut de Recerca contra la Leucèmia Josep Carreras)
Yamamoto, Miyako (Institut Germans Trias i Pujol. Institut de Recerca contra la Leucèmia Josep Carreras)
Yamamoto, Fumiichiro (Institut Germans Trias i Pujol. Institut de Recerca contra la Leucèmia Josep Carreras)
Universitat Autònoma de Barcelona

Date:	2019
Abstract:	Functional paralogous ABO, GBGT1, A3GALT2, and GGTA1 genes encode blood group A and B transferases (AT and BT), Forssman glycolipid synthase (FS), isoglobotriaosylceramide synthase (iGb3S), and α1,3-galactosyltransferase (GT), respectively. These glycosyltransferases transfer N-acetyl-d-galactosamine (GalNAc) or d-galactose forming an α1,3-glycosidic linkage. However, their acceptor substrates are diverse. Previously, we demonstrated that the amino acids at codons 266 and 268 of human AT/BT are crucial to their distinct sugar specificities, elucidating the molecular genetic basis of the ABO glycosylation polymorphism of clinical importance in transfusion and transplantation medicine. We also prepared in vitro mutagenized ATs/BTs having any of 20 possible amino acids at those codons, and showed that those codons determine the transferase activity and sugar specificity. We have expanded structural analysis to include evolutionarily related α1,3-Gal(NAc) transferases. Eukaryotic expression constructs were prepared of AT, FS, iGb3S, and GT, possessing selected tripeptides of AT-specific AlaGlyGly or LeuGlyGly, BT-specific MetGlyAla, FS-specific GlyGlyAla, or iGb3S and GT-specific HisAlaAla, at the codons corresponding to 266-268 of human AT/BT. DNA transfection was performed using appropriate recipient cells existing and newly created, and the appearance of cell surface oligosaccharide antigens was immunologically examined. The results have shown that several tripeptides other than the originals also bestowed transferase activity. However, the repertoire of functional amino acids varied among those transferases, suggesting that structures around those codons differentially affected the interactions between donor nucleotide-sugar and acceptor substrates. It was concluded that different tripeptide sequences at the substrate-binding pocket have contributed to the generation of α1,3-Gal(NAc) transferases with diversified specificities.
Grants:	Agència de Gestió d'Ajuts Universitaris i de Recerca 2014SGR1269 Agència de Gestió d'Ajuts Universitaris i de Recerca 2017SGR529 Instituto de Salud Carlos III PI11-00454
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	ABO Blood-Group System ; Amino Acid Sequence ; Amino Acid Substitution ; Animals ; Codon ; Disaccharides ; Galactans ; Galactosyltransferases ; Humans ; Mice ; Rats ; Substrate Specificity ; Sugars
Published in:	Scientific reports, Vol. 9 Núm. 1 (january 2019) , p. 846, ISSN 2045-2322

DOI: 10.1038/s41598-018-37515-5
PMID: 30696937

11 p, 2.4 MB

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Research literature > UAB research groups literature > Research Centres and Groups (research output) > Health sciences and biosciences > Institut d'Investigació en Ciencies de la Salut Germans Trias i Pujol (IGTP) > Josep Carreras Leukaemia Research Institute
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