4AUP

Tuber borchii Phospholipase A2

Summary for 4AUP

• Entry DOI: 10.2210/pdb4aup/pdb
• Descriptor: PHOSPHOLIPASE A2 GROUP XIII, ACETATE ION, THIOCYANATE ION, ... (4 entities in total)
• Functional Keywords: hydrolase
• Biological source: TUBER BORCHII (WHITISH TRUFFLE)
• Total number of polymer chains: 2
• Total formula weight: 28604.03

Authors

Cavazzini, D.,Meschi, F.,Corsini, R.,Bolchi, A.,Rossi, G.-L.,Einsle, O.,Ottonello, S. (deposition date: 2012-05-18, release date: 2012-12-12, Last modification date: 2024-10-23)

Primary citation

Cavazzini, D.,Meschi, F.,Corsini, R.,Bolchi, A.,Rossi, G.-L.,Einsle, O.,Ottonello, S.
Autoproteolytic Activation of a Symbiosis-Regulated Truffle Phospholipase A2
J.Biol.Chem., 288:1533-, 2013

PubMed Abstract: Fungal phospholipases are members of the fungal/bacterial group XIV secreted phospholipases A(2) (sPLA(2)s). TbSP1, the sPLA(2) primarily addressed in this study, is up-regulated by nutrient deprivation and is preferentially expressed in the symbiotic stage of the ectomycorrhizal fungus Tuber borchii. A peculiar feature of this phospholipase and of its ortholog from the black truffle Tuber melanosporum is the presence of a 54-amino acid sequence of unknown functional significance, interposed between the signal peptide and the start of the conserved catalytic core of the enzyme. X-ray diffraction analysis of a recombinant TbSP1 form corresponding to the secreted protein previously identified in T. borchii mycelia revealed a structure comprising the five α-helices that form the phospholipase catalytic module but lacking the N-terminal 54 amino acids. This finding led to a series of functional studies that showed that TbSP1, as well as its T. melanosporum ortholog, is a self-processing pro-phospholipase A(2), whose phospholipase activity increases up to 80-fold following autoproteolytic removal of the N-terminal peptide. Proteolytic cleavage occurs within a serine-rich, intrinsically flexible region of TbSP1, does not involve the phospholipase active site, and proceeds via an intermolecular mechanism. Autoproteolytic activation, which also takes place at the surface of nutrient-starved, sPLA(2) overexpressing hyphae, may strengthen and further control the effects of phospholipase up-regulation in response to nutrient deprivation, also in the context of symbiosis establishment and mycorrhiza formation.

PubMed: 23192346
DOI: 10.1074/JBC.M112.384156

Experimental method

X-RAY DIFFRACTION (1.9 Å)