Structural basis for heparan sulfate co-polymerase action by the EXT1-2 complex.
Nat Chem Biol
; 19(5): 565-574, 2023 05.
Article
en En
| MEDLINE
| ID: mdl-36593275
ABSTRACT
Heparan sulfate (HS) proteoglycans are extended (-GlcAß1,4GlcNAcα1,4-)n co-polymers containing decorations of sulfation and epimerization that are linked to cell surface and extracellular matrix proteins. In mammals, HS repeat units are extended by an obligate heterocomplex of two exostosin family members, EXT1 and EXT2, where each protein monomer contains distinct GT47 (GT-B fold) and GT64 (GT-A fold) glycosyltransferase domains. In this study, we generated human EXT1-EXT2 (EXT1-2) as a functional heterocomplex and determined its structure in the presence of bound donor and acceptor substrates. Structural data and enzyme activity of catalytic site mutants demonstrate that only two of the four glycosyltransferase domains are major contributors to co-polymer syntheses the EXT1 GT-B fold ß1,4GlcA transferase domain and the EXT2 GT-A fold α1,4GlcNAc transferase domain. The two catalytic sites are over 90 Å apart, indicating that HS is synthesized by a dissociative process that involves a single catalytic site on each monomer.
Texto completo:
1
Bases de datos:
MEDLINE
Asunto principal:
Proteínas
/
Heparitina Sulfato
Límite:
Animals
/
Humans
Idioma:
En
Revista:
Nat Chem Biol
Asunto de la revista:
BIOLOGIA
/
QUIMICA
Año:
2023
Tipo del documento:
Article
País de afiliación:
Estados Unidos