Enterococcus faecalis alpha 1-2-mannosidase (EfMan-I): an efficient catalyst for glycoprotein N-glycan modification.
Li, Y., Li, R., Yu, H., Sheng, X., Wang, J., Fisher, A.J., Chen, X.(2020) FEBS Lett 594: 439-451
- PubMed: 31552675 
- DOI: https://doi.org/10.1002/1873-3468.13618
- Primary Citation of Related Structures:  
6DWO - PubMed Abstract: 
While multiple α 1-2-mannosidases are necessary for glycoprotein N-glycan maturation in vertebrates, a single bacterial α1-2-mannosidase can be sufficient to cleave all α1-2-linked mannose residues in host glycoprotein N-glycans. We report here the characterization and crystal structure of a new α1-2-mannosidase (EfMan-I) from Enterococcus faecalis, a Gram-positive opportunistic human pathogen. EfMan-I catalyzes the cleavage of α1-2-mannose from not only oligomannoses but also high-mannose-type N-glycans on glycoproteins. Its 2.15 Å resolution crystal structure reveals a two-domain enzyme fold similar to other CAZy GH92 mannosidases. An unexpected potassium ion was observed bridging two domains near the active site. These findings support EfMan-I as an effective catalyst for in vitro N-glycan modification of glycoproteins with high-mannose-type N-glycans.
Organizational Affiliation: 
Department of Chemistry, University of California, Davis, CA, USA.