Structure of an inactive (E45Q) variant of a beta-1,4-mannanase, SsGH134, in complex with Man5Structure of an inactive (E45Q) variant of a beta-1,4-mannanase, SsGH134, in complex with Man5

Structural highlights

5jug is a 1 chain structure with sequence from Streptomyces sp. NRRL B-16215. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:X-ray diffraction, Resolution 0.96Å
Ligands:, , ,
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

A0A1L1QK16_9ACTN

Publication Abstract from PubMed

The enzymatic cleavage of beta-1,4-mannans is achieved by endo-beta-1,4-mannanases, enzymes involved in germination of seeds and microbial hemicellulose degradation, and which have increasing industrial and consumer product applications. beta-Mannanases occur in a range of families of the CAZy sequence-based glycoside hydrolase (GH) classification scheme including families 5, 26, and 113. In this work we reveal that beta-mannanases of the newly described GH family 134 differ from other mannanase families in both their mechanism and tertiary structure. A representative GH family 134 endo-beta-1,4-mannanase from a Streptomyces sp. displays a fold closely related to that of hen egg white lysozyme but acts with inversion of stereochemistry. A Michaelis complex with mannopentaose, and a product complex with mannotriose, reveal ligands with pyranose rings distorted in an unusual inverted chair conformation. Ab initio quantum mechanics/molecular mechanics metadynamics quantified the energetically accessible ring conformations and provided evidence in support of a 1C4 --> 3H4double dagger --> 3S1 conformational itinerary along the reaction coordinate. This work, in concert with that on GH family 124 cellulases, reveals how the lysozyme fold can be co-opted to catalyze the hydrolysis of different polysaccharides in a mechanistically distinct manner.

A beta-Mannanase with a Lysozyme-like Fold and a Novel Molecular Catalytic Mechanism.,Jin Y, Petricevic M, John A, Raich L, Jenkins H, Portela De Souza L, Cuskin F, Gilbert HJ, Rovira C, Goddard-Borger ED, Williams SJ, Davies GJ ACS Cent Sci. 2016 Dec 28;2(12):896-903. doi: 10.1021/acscentsci.6b00232. Epub, 2016 Nov 8. PMID:28058278[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

  1. Jin Y, Petricevic M, John A, Raich L, Jenkins H, Portela De Souza L, Cuskin F, Gilbert HJ, Rovira C, Goddard-Borger ED, Williams SJ, Davies GJ. A beta-Mannanase with a Lysozyme-like Fold and a Novel Molecular Catalytic Mechanism. ACS Cent Sci. 2016 Dec 28;2(12):896-903. doi: 10.1021/acscentsci.6b00232. Epub, 2016 Nov 8. PMID:28058278 doi:http://dx.doi.org/10.1021/acscentsci.6b00232

5jug, resolution 0.96Å

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