PUBLICATION
Structure of the polyisoprenyl-phosphate glycosyltransferase GtrB and insights into the mechanism of catalysis
- Authors
- Ardiccioni, C., Clarke, O.B., Tomasek, D., Issa, H.A., von Alpen, D.C., Pond, H.L., Banerjee, S., Rajashankar, K.R., Liu, Q., Guan, Z., Li, C., Kloss, B., Bruni, R., Kloppmann, E., Rost, B., Manzini, M.C., Shapiro, L., Mancia, F.
- ID
- ZDB-PUB-160106-5
- Date
- 2016
- Source
- Nature communications 7: 10175 (Journal)
- Registered Authors
- Keywords
- Biocatalysis, Structural biology, Transferases
- MeSH Terms
-
- Mannosyltransferases/genetics
- Mannosyltransferases/metabolism
- Humans
- Gene Expression Regulation, Enzymologic/physiology*
- Models, Molecular
- PubMed
- 26729507 Full text @ Nat. Commun.
Abstract
The attachment of a sugar to a hydrophobic polyisoprenyl carrier is the first step for all extracellular glycosylation processes. The enzymes that perform these reactions, polyisoprenyl-glycosyltransferases (PI-GTs) include dolichol phosphate mannose synthase (DPMS), which generates the mannose donor for glycosylation in the endoplasmic reticulum. Here we report the 3.0Å resolution crystal structure of GtrB, a glucose-specific PI-GT from Synechocystis, showing a tetramer in which each protomer contributes two helices to a membrane-spanning bundle. The active site is 15 Å from the membrane, raising the question of how water-soluble and membrane-embedded substrates are brought into apposition for catalysis. A conserved juxtamembrane domain harbours disease mutations, which compromised activity in GtrB in vitro and in human DPM1 tested in zebrafish. We hypothesize a role of this domain in shielding the polyisoprenyl-phosphate for transport to the active site. Our results reveal the basis of PI-GT function, and provide a potential molecular explanation for DPM1-related disease.
Genes / Markers
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Orthology
Engineered Foreign Genes
Mapping