Protein disulfide-isomerase involved in chloroplast development in cotyledons. Involved in the process of vesicle-derived thylakoid formation, probably at the level of the integration and folding of LHCB proteins at the initial location of integration. Acts only in germinating seeds after dormancy, during the transition from heterotrophic to autotrophic growth. Catalyzes the rearrangement of -S-S- bonds in proteins. Homomer. Interacts with LHCB1 proteins, but is not part of the signal recognition particle protein targeting pathway. Associates with multiple thylakoid complexes. Expressed in roots, rosette and cauline leaves, stems, inflorescences and young siliques of light-grown plants, but not in etiolated seedlings or in senescing tissues. Very low expression in etiolated seedlings, but gradual increase upon illumination with a maximum after 6 hours. Expressed mainly in young plants grown under light conditions. Albino cotyledons but normal green true leaves. Its sequence is related to the DnaJ family but lacks the J domain. The CR-type-like region is similar to CR-type zinc-fingers.