Erratum to: Purification and characterization of a nitrilase from Aspergillus niger K10.

Abstract

Erratumto:ApplMicrobiolBiotechnol(2006)73:567–575DOI 10.1007/s00253-006-0503-6The previous article reported on the biochemical characteriza-tion of a nitrilase purified from Aspergillus niger K10. Theamino acid sequence of this enzyme was recently analyzed bymassspectroscopywhichreveale dthattheN-terminalsequencereported in Fig. 3A (by KB) in the previous article was incor-rect. This N-terminal sequence (XAPVLKKYKAAXVNXE),which was highly homologous to those of a number of hypo-thetical proteins in genus Aspergillus (Aspergillus fumigatusAf29, Aspergillus oryzae, Aspergillus nidulans FGSC A4) didnot belong to the enzyme purified and characterized in theprevious article. Mass spectrum analyses of this enzyme wererecently performed as follows. Briefly, the peptides wereextracted after in gel digestion of the enzyme withtrypsin and analyzed by MALDI-ToF MS using BrukerBiflex IV (Bruker Daltonics, Germany). Alternatively,the peptides were analyzed by using UHPLC DionexUltimate3000 RSLC nano (Dionex, Germany) equippedwith a ESI-Q-ToF Maxis Impact (Bruker Daltonics,Germany) mass spectrometer. Spectra were interpreted us-ing Mascot software (Matrix Science, UK). These analyses(Fig. S1) suggested a 42.5-58.1 % sequence coverage ofthe enzyme with a putative nitrilase from Aspergilluskawachii IFO 4308 (gi|358373570) having N-terminalsequence MSHDGPKTIRVAAVQA (Fig. 1).The N-terminal amino acid sequence reported in theprevious article belonged to another enzyme encoded inthe same strain (gb|ABX75546). This enzyme was laterexpressed in E. coli, purified and characterized, and itssubstrate specificity was found to be different from that ofthe nitrilase purified in A. niger K10 (Kaplan et al. 2011).This was hypothesized to be caused by a misfolding or by aposttranslational modification (Kaplan et al. 2011) but thishypothesis has been corrected according to the new MSanalyses (Kaplan et al., Corrigendum to: Heterologous ex-pression, purification and characterization of nitrilase fromAspergillus niger K10 (BMC Biotechnol (2011) 11:2).BMC Biotechnol, submitted manuscript). The aforemen-tioned enzyme from A. nidulans FGSC A4 was later char-acterized as a cyanide hydratase (Basile et al. 2008). In