PDBsum entry 5o2x

Oxidoreductase

PDB id: 5o2x

Contents

Protein chain

248 a.a.

Ligands

NAG ×2

MAN ×15

SO4 ×3

Metals

_CU

Waters ×407

PDB id:

5o2x

Name:

Oxidoreductase

Title:

Extended catalytic domain of h. Jecorina lpmo9a a.K.A eg4

Structure:

Glycoside hydrolase family 61. Chain: a. Engineered: yes. Other_details: first residue (histidine) is methylated: 4-methyl- histidine (=>hic)

Source:

Trichoderma reesei qm6a. Organism_taxid: 431241. Gene: cel61a, triredraft_73643. Expressed in: trichoderma reesei rut c-30. Expression_system_taxid: 1344414

Resolution:

0.95Å R-factor: 0.116 R-free: 0.127

Authors:

H.Hansson,S.Karkehabadi,N.E.Mikkelsen,M.Sandgren,B.Kelemen,T.Kaper

Key ref:

H.Hansson et al. (2017). High-resolution structure of a lytic polysaccharide monooxygenase fromHypocrea jecorinareveals a predicted linker as an integral part of the catalytic domain. J Biol Chem, 292, 19099-19109. PubMed id: 28900033

Date:

23-May-17 Release date: 20-Sep-17

Protein chain

G0R6T8  (G0R6T8_HYPJQ) -  AA9 family lytic polysaccharide monooxygenase cel61A from Hypocrea jecorina (strain QM6a)

Seq: 344 a.a.

Struc: 248 a.a.*

* PDB and UniProt seqs differ at 1 residue position (black cross)

Enzyme reactions

• Enzyme class: E.C.1.14.99.56 - lytic cellulose monooxygenase (C4-dehydrogenating).
• Reaction: [(1->4)-beta-D-glucosyl]n+m + reduced acceptor + O2 = 4-dehydro-beta-D- glucosyl-[(1->4)-beta-D-glucosyl]n-1 + [(1->4)-beta-D-glucosyl]m + acceptor + H2O
• Cofactor: Cu(+)

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

Key reference

J Biol Chem 292:19099-19109 (2017)

PubMed id: 28900033

High-resolution structure of a lytic polysaccharide monooxygenase fromHypocrea jecorinareveals a predicted linker as an integral part of the catalytic domain.

H.Hansson, S.Karkehabadi, N.Mikkelsen, N.R.Douglas, S.Kim, A.Lam, T.Kaper, B.Kelemen, K.K.Meier, S.M.Jones, E.I.Solomon, M.Sandgren.

ABSTRACT

For decades, the enzymes of the fungusHypocrea jecorinahave served as a model system for the breakdown of cellulose. Three-dimensional structures for almost allH. jecorinacellulose-degrading enzymes are available, except forHjLPMO9A, belonging to the AA9 family of lytic polysaccharide monooxygenases (LPMOs). These enzymes enhance the hydrolytic activity of cellulases and are essential for cost-efficient conversion of lignocellulosic biomass. Here, using structural and spectroscopic analyses, we found that nativeHjLPMO9A contains a catalytic domain and a family-1 carbohydrate-binding module (CBM1) connected via a linker sequence. A C terminally truncated variant ofHjLPMO9A containing 21 residues of the predicted linker was expressed at levels sufficient for analysis. Here, using structural, spectroscopic, and biochemical analyses, we found that this truncated variant exhibited reduced binding to and activity on cellulose compared with the full-length enzyme. Importantly, a 0.95-Å resolution X-ray structure of truncatedHjLPMO9A revealed that the linker forms an integral part of the catalytic domain structure, covering a hydrophobic patch on the catalytic AA9 module. We noted that the oxidized catalytic center contains a Cu(II) coordinated by two His ligands, one of which has a His-brace in which the His-1 terminal amine group also coordinates to a copper. The final equatorial position of the Cu(II) is occupied by a water-derived ligand. The spectroscopic characteristics of the truncated variant were not measurably different from those of full-lengthHjLPMO9A, indicating that the presence of the CBM1 module increases the affinity ofHjLPMO9A for cellulose binding, but does not affect the active site.