Structure and catalytic cycle of β-1, 4-galactosyltransferase

B Ramakrishnan, E Boeggeman, V Ramasamy… - Current opinion in …, 2004 - Elsevier
B Ramakrishnan, E Boeggeman, V Ramasamy, PK Qasba
Current opinion in structural biology, 2004Elsevier
β-1, 4-galactosyltransferase-1, a housekeeping enzyme that functions in the synthesis of
glycoconjugates, has two flexible loops, one short and one long. Upon binding a metal ion
and UDP-galactose, the loops change from an open to a closed conformation, repositioning
residues to lock the ligands in place. Residues at the N-terminal region of the long loop form
the metal-binding site and those at the C-terminal region form a helix, which becomes part of
the binding site for the oligosaccharide acceptor; the remaining residues cover the bound …
β-1,4-galactosyltransferase-1, a housekeeping enzyme that functions in the synthesis of glycoconjugates, has two flexible loops, one short and one long. Upon binding a metal ion and UDP-galactose, the loops change from an open to a closed conformation, repositioning residues to lock the ligands in place. Residues at the N-terminal region of the long loop form the metal-binding site and those at the C-terminal region form a helix, which becomes part of the binding site for the oligosaccharide acceptor; the remaining residues cover the bound sugar-nucleotide. After binding of the oligosaccharide acceptor and transfer of the galactose moiety, the product disaccharide unit is ejected and the enzyme returns to the open conformation, repeating the catalytic cycle.
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