Analysis of two incompletely spliced Arabidopsis cDNAs encoding novel types of peroxidase

Most known class III peroxidase genes contain three introns at conserved po sitions. Two Arabidopsis cDNAs (ESTs), encoding novel type peroxidases ATP9 a and ATP15a were sequenced, and found to contain inserts for intron 2. PCR and sequence analysis of genomic DNA revealed that the atp9a gene contains all three introns, whereas atp15a contains only introns 2 and 3. The ATP15 a cDNA intron contained a single base substitution reducing the splicing po tential significantly as compared with the genomic sequence. The putative e nzymes share essential catalytic and structural features with horseradish p eroxidase, despite a pair-wise sequence identity of only 40-45% among the t hree. (C) 1998 Elsevier Science B.V. All rights reserved.