Interaction between the N-terminal and middle regions is essential for the in vivo function of HSP90 molecular chaperone.
At the primary structure level, the 90-kDa heat shock protein (HSP90) is composed of three regions: the N-terminal (Met(1)-Arg(400)), middle (Glu(401)-Lys(615)), and C-terminal (Asp(621)-Asp(732)) regions. In the present study, we investigated potential subregion structures of these three regions and their roles. Limited proteolysis revealed that the N-terminal region could be split into two fragments carrying residues Met(1) to Lys(281) (or Lys(283)) and Glu(282) (or Tyr(284)) to Arg(400). The former is known to carry the ATP-binding domain. The fragments carrying the N-terminal two-thirds (Glu(401)-Lys(546)) and C-terminal one-third of the middle region were sufficient for the interactions with the N- and C-terminal regions, respectively. Yeast HSC82 that carried point mutations in the middle region causing deficient binding to the N-terminal region could not support the growth of HSP82-depleted cells at an elevated temperature. Taken together, our data show that the N-terminal and middle regions of the HSP90 family protein are structurally divided into two respective subregions. Moreover, the interaction between the N-terminal and middle regions is essential for the in vivo function of HSP90 in yeast.
Department of Dental Anesthesiology, Nagasaki University School of Dentistry, 1-7-1 Sakamoto, Nagasaki 852-8588, Japan.
Shigeki
S
Matsumoto
Etsuko
E
Tanaka
Takayuki K
TK
Nemoto
Toshio
T
Ono
Takashi
T
Takagi
Jun
J
Imai
Yoko
Y
Kimura
Ichiro
I
Yahara
Takeshi
T
Kobayakawa
Takao
T
Ayuse
Kumiko
K
Oi
Akio
A
Mizuno
D000595:Amino Acid Sequence; D004591:Electrophoresis, Polyacrylamide Gel; D018841:HSP90 Heat-Shock Proteins / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D006868:Hydrolysis; D008969:Molecular Sequence Data; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D020798:Two-Hybrid System Techniques
D018841:HSP90 Heat-Shock Proteins