Abstract: Heat shock proteins (Hsp),representing an important molecular chaperone in eukaryotic cells,is a common response to development,stress resistance,signal transduction and evolution of plants.The relationship between the structure and functional roles was elucidated in Hsp90 based on the generation of full-length cDNAs from Senecio scandens Buch.-Ham.ex D.Don.Sequence analysis of Hsp90-3 gene indicated that it shared 93.71% identity with Arabidopsis thaliana (GenBank accession: NP_200412.1),encoding a protein composed of 699 amino acid residues with the predicted molecular weight of 79.78 kD and theoretical isoelectric point of 5.08.Moreover,the distribution of Hsp90-3 was involved in the endomembrane system such as nuclei,peroxisomes,chloroplast thylakoid membranes,and chloroplast matrices in the present study.Three-dimensional measurement revealed that the Hsp90-3 protein was composed of three structural domains and one link region.These results suggested that Hsp90-3 played a critical role in molecular chaperone,signal transduction,transcriptional regulation and stress-response in higher plants.