title: The crystal structure of the C-terminal fragment of yeast Hsp40 Ydj1 reveals novel dimerization motif for Hsp40.
abstract: The molecular chaperone Hsp40 functions as a dimer. The dimer formation is critical for Hsp40 molecular chaperone activity to facilitate Hsp70 to refold non-native polypeptides. We have determined the crystal structure of the C-terminal fragment of yeast Hsp40 Ydj1 that is responsible for Ydj1 dimerization by MAD method. The C-terminal fragment of Ydj1 comprises of the domain III of Ydj1 and the Ydj1 C-terminal dimerization motif. The crystal structure indicates that the dimerization motif of type I Hsp40 Ydj1 differs significantly from that of yeast type II Hsp40. The C terminus of type I Hsp40 Ydj1 from one monomer forms beta-strands with the domain III from the other monomer in the homo-dimer. The L372 from Ydj1 C terminus inserts its side-chain into a hydrophobic pocket on domain III. The modeled full-length Ydj1 dimer structure reveals that a large cleft is formed between the two monomers. The domain IIs of Ydj1 monomers that contain the zinc-finger motifs points directly against each other.
authors.affiliation: Department of Cell Biology, Center for Biophysical Sciences and Engineering, University of Alabama at Birmingham, Birmingham, AL 35294-0005, USA.
authors.forename: Yunkun
authors.initials: Y
authors.lastname: Wu
authors.forename: Jingzhi
authors.initials: J
authors.lastname: Li
authors.forename: Zhongmin
authors.initials: Z
authors.lastname: Jin
authors.forename: Zhengqing
authors.initials: Z
authors.lastname: Fu
authors.forename: Bingdong
authors.initials: B
authors.lastname: Sha
mesh_terms: D020816:Amino Acid Motifs; D018360:Crystallography, X-Ray; D019281:Dimerization; D050956:HSP40 Heat-Shock Proteins; D006360:Heat-Shock Proteins / Q000737:chemistry* / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry* / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D012441:Saccharomyces cerevisiae / Q000737:chemistry*; D029701:Saccharomyces cerevisiae Proteins; D016415:Sequence Alignment
chemical_list: D050956:HSP40 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D010446:Peptide Fragments; D029701:Saccharomyces cerevisiae Proteins; C070319:YDJ1 protein, S cerevisiae