Weiss C, Goloubinoff P
Department of Botany, Institute of Life Sciences, Hebrew University of Jerusalem, Israel.
J Biol Chem. 1995 Jun 9;270(23):13956-60. doi: 10.1074/jbc.270.23.13956.
The highly conserved aspartic acid residue at position 87 of the Escherichia coli chaperonin GroEL was mutated to glutamic acid. When expressed in an E. coli groEL mutant strain deficient for phage morphogenesis, plasmid-encoded GroEL mutant D87E restored T4 phage morphogenesis. It did not, however, reactivate the transcription of a recombinant luciferase operon from Vibrio fischeri. In vitro, GroEL mutant D87E was found to be impaired in the ability to bind nonnative proteins and to hydrolyze ATP, resulting in less efficient refolding of urea-denatured ribulose-1,5-bisphosphate carboxylase/oxygenase. Mutant oligomer D87E GroEL14 was able to bind GroES7 as efficiently as wild-type GroEL14. The conserved aspartic acid residue at position 87 located in the equatorial domain of GroEL (Braig, K., Otwinowski, Z., Hegde, R., Boisvert, D.C., Joachimiak, A., Horwich, A.L., and Sigler, P.B. (1994) Nature 371, 578-586) is thus inferred to have a dual effect on the binding of nonnative proteins to the GroEL14 core chaperonin and on ATP hydrolysis.
将大肠杆菌伴侣蛋白GroEL第87位高度保守的天冬氨酸残基突变为谷氨酸。当在缺乏噬菌体形态发生的大肠杆菌groEL突变菌株中表达时，质粒编码的GroEL突变体D87E恢复了T4噬菌体的形态发生。然而，它并未重新激活费氏弧菌重组荧光素酶操纵子的转录。在体外，发现GroEL突变体D87E结合非天然蛋白质和水解ATP的能力受损，导致尿素变性的1,5-二磷酸核酮糖羧化酶/加氧酶的重折叠效率降低。突变体寡聚体D87E GroEL14与野生型GroEL14一样能够有效地结合GroES7。因此可以推断，位于GroEL赤道结构域的第87位保守天冬氨酸残基（Braig, K., Otwinowski, Z., Hegde, R., Boisvert, D.C., Joachimiak, A., Horwich, A.L., and Sigler, P.B. (1994) Nature 371, 578 - 586）对非天然蛋白质与GroEL14核心伴侣蛋白的结合以及ATP水解具有双重作用。
