PDBsum entry: 1hcu

Glycosylation

PDB id: 1hcu

Contents

Protein chains

488 a.a. *

Ligands

NAG ×10

Metals

_CA ×4

Waters ×1094

* Residue conservation analysis

PDB id:

1hcu

Name:

Glycosylation

Title:

Alpha-1,2-mannosidase from trichoderma reesei

Structure:

Alpha-1,2-mannosidase. Chain: a, b, c, d. Synonym: 1,2-a-d-mannosidase. Engineered: yes

Source:

Trichoderma reesei. Organism_taxid: 51453. Expressed in: pichia pastoris. Expression_system_taxid: 4922

Resolution:

2.37Å R-factor: 0.177 R-free: 0.232

Authors:

F.Van Petegem,H.Contreras,R.Contreras,J.Van Beeumen

Key ref:

F.Van Petegem et al. (2001). Trichoderma reesei alpha-1,2-mannosidase: structural basis for the cleavage of four consecutive mannose residues. J Mol Biol, 312, 157-165. PubMed id: 11545593 DOI: 10.1006/jmbi.2001.4946

Date:

09-May-01 Release date: 18-Oct-01

Protein chains

Q9P8T8  (Q9P8T8_TRIRE) -  1,2-a-D-mannosidase

Seq: 523 a.a.

Struc: 488 a.a.

 Gene Ontology (GO) functional annotation 

• Cellular component: membrane (1 term)
• Biochemical function: calcium ion binding (2 terms)

DOI no: 10.1006/jmbi.2001.4946

J Mol Biol 312:157-165 (2001)

PubMed id: 11545593

Trichoderma reesei alpha-1,2-mannosidase: structural basis for the cleavage of four consecutive mannose residues.

F.Van Petegem, H.Contreras, R.Contreras, J.Van Beeumen.

ABSTRACT

The process of N-glycosylation of eukaryotic proteins involves a range of host enzymes that delete or add saccharide monomers. While endoplasmic reticulum (E.R.) mannosidases cleave only one mannose to produce the Man8B isomer, an alpha-1,2-mannosidase from Trichoderma reesei can sequentially cleave all four 1,2-linked mannose sugars from a Man(9)GlcNAc(2) oligosaccharide, a feature reminiscent of the activity of Golgi mannosidases. We now report the structure of the T. reesei enzyme at 2.37 A resolution. The enzyme folds as an (alpha alpha)(7) barrel. The substrate-binding site of the T. reesei mannosidase differs appreciably from the Saccharomyces cerevisiae enzyme. In the former, shorter loops at the surface allow substrate protein to come closer to the catalytic site. There is more internal space available, so that different oligosaccharide conformations are sterically allowed in the T. reesei alpha-1,2-mannosidase.

Selected figure(s)

Figure 1.
Figure 1. Overall structure of the T. reesei a-1,2-mannosidase. (a) Top view, and (b) side view of the (aa)[7] barrel. b-Strands are shown in blue, and a-helices are shown in green. An extra a-helix at the substrate-binding site is represented in red.

Figure 2.
Figure 2. Stereo figure of a superposition of the backbones of the T. reesei (red) and S. cerevisiae (blue) a-1,2-mannosidases. The N and C terminus for the Trichoderma protein are indicated. The orientation of the molecules is the same as in Figure 1(b).

The above figures are reprinted by permission from Elsevier: J Mol Biol (2001, 312, 157-165) copyright 2001.

Figures were selected by an automated process.