Characterization of polygalacturonases.

Lei et al. [Gene 117 (1992) 119-124] recently published the nucleotide sequence of the peh gene of Erwinia carotovora subsp. carotovora (Ecc) and a characterization of its product endopolygalacturonase (Peh). The gene appears highly similar to previously described peh sequences of Ecc [Hinton et al., Mol. Microbiol. 4 (1990) 1029-1036; Saarilahti et al., Mol. Microbiol. 4 (1990) 1037-1044] which were not cited in the article. Ecc carries a single peh gene whose product, Peh, is here shown to share similarity with the two Pehs characterized thus far and a Peh-like protein of eukaryotic origin at the amino acid (aa) sequence level. Additionally, a highly conserved region within their C-terminal domains was found to share local similarity with two 13-aa segments of an otherwise distinct exo-poly-alpha-D-galacturonosidase (exo-Peh), suggesting that these segments might be required for enzyme activity in both Peh and exo-Peh.