Skorko-Glonek Joanna, Laskowska Ewa, Sobiecka-Szkatula Anna, Lipinska Barbara
University of Gdansk, Department of Biochemistry, Kladki 24, 80-822 Gdansk, Poland.
Arch Biochem Biophys. 2007 Aug 1;464(1):80-9. doi: 10.1016/j.abb.2007.04.006. Epub 2007 Apr 23.
The protective action of chaperone-like activity of HtrA protease against protein aggregation was studied. High levels of proteolytically inactive HtrAS210A (active center serine replaced by alanine) suppressed the temperature-sensitive phenotype of the htrA mutants. The ability of HtrAS210A to alleviate the lethality of htrA bacteria at high temperatures correlated well with the observed decrease of cellular level of large protein aggregates in cells overproducing HtrAS210A. The in vitro experiments proved that HtrA was very efficient in inhibiting the unfolded substrate (lysozyme) aggregation over a wide range of temperatures (30-45 degrees C). HtrA was able to bind to the denatured polypeptides and as a consequence limited their ability to form large aggregates. Our results suggest that HtrA may protect the bacterial cells from deleterious effects of heat shock not only by degrading the damaged proteins but by combination of the proteolytic and chaperoning activities.
研究了HtrA蛋白酶的伴侣样活性对蛋白质聚集的保护作用。高水平的蛋白水解无活性的HtrAS210A（活性中心丝氨酸被丙氨酸取代）抑制了htrA突变体的温度敏感表型。HtrAS210A在高温下减轻htrA细菌致死率的能力与在过量产生HtrAS210A的细胞中观察到的大蛋白质聚集体细胞水平的降低密切相关。体外实验证明，HtrA在很宽的温度范围（30-45摄氏度）内非常有效地抑制未折叠底物（溶菌酶）的聚集。HtrA能够结合变性多肽，从而限制它们形成大聚集体的能力。我们的结果表明，HtrA不仅可以通过降解受损蛋白质，还可以通过蛋白水解和伴侣活性的结合，保护细菌细胞免受热休克的有害影响。
