Characterization of the glyoxysomal isocitrate lyase genes of Aspergillus nidulans (acuD) and Neurospora crassa (acu-3)

Abstract

The nucleotide sequences of the genes encoding the acetate-inducible glyoxylate cycle enzyme isocitrate lyase from the ascomycete fungi Aspergillus nidulans (acuD) and Neurospora crassa (acu-3) are presented. The respective A. nidulans and N. crassa genes are interrupted at identical positions by two introns and encode proteins of 538 and 543 amino acids, which have 75% identity. The predicted protein sequences do not demonstrate the C-terminal tripeptide S-K-L that has been implicated in peroxisomal targeting and found in the glyoxysomally located enzyme malate synthase from the same species. However, the protein sequences do exhibit a partial repeat which, in common with malate synthase, is located in regions that are absent from, or non-homologous with, the E. coli enzyme, which is not compartmentalized.