5MII

Crystal structure of carboxyl esterase 2 (TmelEST2) from mycorrhizal fungus Tuber melanosporum

Summary for 5MII

• Entry DOI: 10.2210/pdb5mii/pdb
• Descriptor: Carboxyl esterase 2 (2 entities in total)
• Functional Keywords: lipase alpha/beta hydrolase fold archaebacterial-like enzymes pmsf, hydrolase
• Biological source: Tuber melanosporum (strain Mel28) (Perigord black truffle)
• Total number of polymer chains: 4
• Total formula weight: 150391.48

Authors

Zanotti, G.,Vallese, F.,Cavazzini, D.,Ottonello, S. (deposition date: 2016-11-28, release date: 2017-08-23, Last modification date: 2018-01-24)

Primary citation

Cavazzini, D.,Grossi, G.,Levati, E.,Vallese, F.,Montanini, B.,Bolchi, A.,Zanotti, G.,Ottonello, S.
A family of archaea-like carboxylesterases preferentially expressed in the symbiotic phase of the mycorrhizal fungus Tuber melanosporum.
Sci Rep, 7:7628-7628, 2017

PubMed Abstract: An increasing number of esterases is being revealed by (meta) genomic sequencing projects, but few of them are functionally/structurally characterized, especially enzymes of fungal origin. Starting from a three-member gene family of secreted putative "lipases/esterases" preferentially expressed in the symbiotic phase of the mycorrhizal fungus Tuber melanosporum ("black truffle"), we show here that these enzymes (TmelEST1-3) are dimeric, heat-resistant carboxylesterases capable of hydrolyzing various short/medium chain p-nitrophenyl esters. TmelEST2 was the most active (kcat = 2302 s for p-nitrophenyl-butyrate) and thermally stable (T = 68.3 °C), while TmelEST3 was the only one displaying some activity on tertiary alcohol esters. X-ray diffraction analysis of TmelEST2 revealed a classical α/β hydrolase-fold structure, with a network of dimer-stabilizing intermolecular interactions typical of archaea esterases. The predicted structures of TmelEST1 and 3 are overall quite similar to that of TmelEST2 but with some important differences. Most notably, the much smaller volume of the substrate-binding pocket and the more acidic electrostatic surface profile of TmelEST1. This was also the only TmelEST capable of hydrolyzing feruloyl-esters, suggestinng a possible role in root cell-wall deconstruction during symbiosis establishment. In addition to their potential biotechnological interest, TmelESTs raise important questions regarding the evolutionary recruitment of archaea-like enzymes into mesophilic subterranean fungi such as truffles.

PubMed: 28794466
DOI: 10.1038/s41598-017-08007-9

Experimental method

X-RAY DIFFRACTION (2.372 Å)