CHARACTERIZATION OF A HIGHLY EXPRESSED LIGNIN PEROXIDASE-ENCODING GENE FROM THE BASIDIOMYCETE PHANEROCHAETE-CHRYSOSPORIUM

The genomic clone, LG2, encoding LiP2, the major lignin peroxidase (LiP) isozyme from Phanerochaete chrysosporium strain OGC101, was isolated and characterized. The 5'-untranslated region of LG2 contains sequences similar to CRE and XRE promoter elements. Comparison with its transcript indicates that eight introns, each less than 59 bp, interrupt the coding sequence. Comparison with genes encoding other LiP isozymes shows five related patterns of intron location, whose incidence coincides with described LiP structural subfamilies. Codon bias indices calculated for all known P. chrysosporium genes, including trpC and genes encoding LiP, MnP, and exco-cellobiohydrolase I, demonstrate that LG2 has the most biased codon usage. We conclude that subdivisions of the LiP family may be based on intron location in the encoding genes, and that ranking of isozyme production levels can be estimated by the extent of bias in codon usage in the cognate gene.