Structural and functional characteristics of 11 B. distachyon PDI and PDI-like proteins.

A, active site containing thioredoxin-like domain; b, inactive thioredoxin-like domain (superscript is included to distinguish between domains of proteins containing more than one a and b domain on the basis of their positions and not on the basis of sequence homology); c, acidic segment; D, Erp29c domain; t, transmembrane domain. The position of conserved charge pair sequence and arginine residues that are considered to be important for the catalytic activity are determined on the basis of multiple alignments of the a type domains of Brachypodium distachyon PDI-like proteins and the classical PDI of Oryza sativa [LOC_Os11g09280.1] (Figure 4). ND, not determined because BdPDIL8-1 lacks a putative N-terminal signal peptide. Proteins without signal peptides are unlikely to be exposed to O/N-glycosilation machinery and thus may not be glycosylated in vivo even though they contain potential motifs.