Crystal structures of Phanerochaete chrysosporium pyranose 2-oxidase suggest that the N-terminus acts as a propeptide that assists in homotetramer assembly
2013 (English)In: FEBS Open Bio, E-ISSN 2211-5463, Vol. 3, 496-504 p.Article in journal (Refereed) Published
The flavin-dependent homotetrameric enzyme pyranose 2-oxidase (P2O) is found mostly, but not exclusively, in lignocellulose-degrading fungi where it catalyzes the oxidation of β-. d-glucose to the corresponding 2-keto sugar concomitantly with hydrogen peroxide formation during lignin solubilization. Here, we present crystal structures of P2O from the efficient lignocellulolytic basidiomycete Phanerochaete chrysosporium. Structures were determined of wild-type PcP2O from the natural fungal source, and two variants of recombinant full-length PcP2O, both in complex with the slow substrate 3-deoxy-3-fluoro-. β-. d-glucose. The active sites in PcP2O and P2O from Trametes multicolor (TmP2O) are highly conserved with identical substrate binding. Our structural analysis suggests that the 17°C higher melting temperature of PcP2O compared to TmP2O is due to an increased number of intersubunit salt bridges. The structure of recombinant PcP2O expressed with its natural N-terminal sequence, including a proposed propeptide segment, reveals that the first five residues of the propeptide intercalate at the interface between A and B subunits to form stabilizing, mainly hydrophobic, interactions. In the structure of mature PcP2O purified from the natural source, the propeptide segment in subunit A has been replaced by a nearby loop in the B subunit. We propose that the propeptide in subunit A stabilizes the A/B interface of essential dimers in the homotetramer and that, upon maturation, it is replaced by the loop in the B subunit to form the mature subunit interface. This would imply that the propeptide segment of PcP2O acts as an intramolecular chaperone for oligomerization at the A/B interface of the essential dimer.
Place, publisher, year, edition, pages
2013. Vol. 3, 496-504 p.
Crystal structure, Lignin degradation, Oligomerization, Propeptide, Pyranose 2-oxidase, Thermostability
IdentifiersURN: urn:nbn:se:kth:diva-139900DOI: 10.1016/j.fob.2013.10.010ISI: 000339569800078ScopusID: 2-s2.0-84888118395OAI: oai:DiVA.org:kth-139900DiVA: diva2:687798
FunderSwedish Research Council, 2008-4045 2011-5768
QC 201401152014-01-152014-01-152015-04-29Bibliographically approved