title: Structure of the lectin mannose 6-phosphate receptor homology (MRH) domain of glucosidase II, an enzyme that regulates glycoprotein folding quality control in the endoplasmic reticulum.
abstract: Here we report for the first time the three-dimensional structure of a mannose 6-phosphate receptor homology (MRH) domain present in a protein with enzymatic activity, glucosidase II (GII). GII is involved in glycoprotein folding in the endoplasmic reticulum. GII removes the two innermost glucose residues from the Glc3Man9GlcNAc2 transferred to nascent proteins and the glucose added by UDP-Glc:glycoprotein glucosyltransferase. GII is composed of a catalytic GIIα subunit and a regulatory GIIβ subunit. GIIβ participates in the endoplasmic reticulum localization of GIIα and mediates in vivo enhancement of N-glycan trimming by GII through its C-terminal MRH domain. We determined the structure of a functional GIIβ MRH domain by NMR spectroscopy. It adopts a β-barrel fold similar to that of other MRH domains, but its binding pocket is the most shallow known to date as it accommodates a single mannose residue. In addition, we identified a conserved residue outside the binding pocket (Trp-409) present in GIIβ but not in other MRHs that influences GII glucose trimming activity.
authors.affiliation: Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin 53226.
authors.forename: Linda J
authors.initials: LJ
authors.lastname: Olson
authors.affiliation: Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, C1405BWE Buenos Aires, Argentina.
authors.forename: Ramiro
authors.initials: R
authors.lastname: Orsi
authors.affiliation: Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, C1405BWE Buenos Aires, Argentina.
authors.forename: Solana G
authors.initials: SG
authors.lastname: Alculumbre
authors.affiliation: Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin 53226.
authors.forename: Francis C
authors.initials: FC
authors.lastname: Peterson
authors.affiliation: Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, C1405BWE Buenos Aires, Argentina.
authors.forename: Ivan D
authors.initials: ID
authors.lastname: Stigliano
authors.affiliation: Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, C1405BWE Buenos Aires, Argentina.
authors.forename: Armando J
authors.initials: AJ
authors.lastname: Parodi
authors.affiliation: Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, C1405BWE Buenos Aires, Argentina; School of Sciences, University of Buenos Aires, C1428EHA Buenos Aires, Argentina. Electronic address: cdalessio@leloir.org.ar.
authors.forename: Cecilia
authors.initials: C
authors.lastname: D'Alessio
authors.affiliation: Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin 53226. Electronic address: ndahms@mcw.edu.
authors.forename: Nancy M
authors.initials: NM
authors.lastname: Dahms
mesh_terms: D018360:Crystallography, X-Ray; D004721:Endoplasmic Reticulum / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D006023:Glycoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008358:Mannose / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017510:Protein Folding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D012568:Schizosaccharomyces / Q000201:enzymology* / Q000235:genetics; D029702:Schizosaccharomyces pombe Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000520:alpha-Glucosidases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D006023:Glycoproteins; D029702:Schizosaccharomyces pombe Proteins; C034251:4-nitrophenyl-alpha-glucosidase; D000520:alpha-Glucosidases; D008358:Mannose
keywords: Endoplasmic Reticulum (ER); Glucosidase II β; Glycobiology; Glycoprotein; MRH Domain; N-Glycan; NMR; Structural Biology