Purification and Some Properties of NAD‐Glycohydrolase from Conidia of Neurospora crassa

Abstract

NAD‐glycohydrolase from conidia of Neurospora crassa was purified by affinity chromatography, using 4‐methylnicotinamide adenine dinucleotide as ligand immobilized onto Sepharose through a hydrophilic spacer arm. The pure enzyme is a glycoprotein with an isoelectric point of 5.5 and a molecular weight of 33000 as determined by sodium dodecylsulphate gel electrophoresis. The specific activity is the highest so far found for NAD‐glycohydrolases and in various aspects the enzyme is different from that isolated from mycelia ofN. crussa grown in a ‘zinc‐deficient’ medium.

Discovery of fungal surface NADases predominantly present in pathogenic species

“…1E). This is in line with studies that showed glycosylation of N. crassa NADase and could explain the discrepancy between the observed and theoretical molecular masses 13 . A predicted N-terminal secretory signal peptide in the A. fumigatus protein was confirmed by LC-MS/MS (highlighted in blue in Fig.…”

“…Identification of fungal surface NADases. Since conidia from N. crassa have been known to exhibit NADase activity, we tested whether conidia from the human opportunistic pathogen A. fumigatus may have a similar activity 13 . Using the fluorescent NAD + analogue nicotinamide 1, N6-ethenoadenine dinucleotide (εNAD + ) we detected robust cleavage on the surface of A. fumigatus conidia from the strain CEA17ΔakuB, indicating the presence of one or more NADases (Fig.…”

“…Even though ubiquitously found in bacteria, plants and animals no NADase has so far been identified in fungi. Earlier reports indicated the presence of NADase activity on conidia and hyphae of the filamentous fungus Neurospora crassa 12,13 . However, the molecular identity of this activity has remained obscure.…”

Vibrio fischeriGeneshvnAandhvnBEncode Secreted NAD+-Glycohydrolases

“…This V max is 10 2 -to 10 4 -fold higher than the minor NADase activity reported in certain other bacterial ARTases (15,(39)(40)(41). It is also a higher activity than that reported for NADases purified from rabbit erythrocytes and Bungarus fasciatus venom, while lower than the activity of NADases purified from N. crassa and streptococci (12,25,35,58). Thus, the specific NADase activity of HvnA lies within a range reported for NADases and would be exceptionally high for the background NADase activity of an ARTase.…”