EA Recherche en Vigne et Vin, Université de Bourgogne, Dijon, France.
FEMS Microbiol Lett. 2010 Aug 1;309(1):8-15. doi: 10.1111/j.1574-6968.2010.01999.x. Epub 2010 Apr 27.
The small heat shock protein (smHsp) Lo18 from lactic acid bacteria Oenococcus oeni reduces in vitro thermal aggregation of proteins and modulates the membrane fluidity of native liposomes. An absence of information relating to the way in which the smHsp demonstrates a stabilizing effect for both proteins and membranes prompted this study. We expressed three Lo18 proteins with amino acid substitutions in Escherichia coli to investigate their ability to prevent E. coli protein aggregation and their capacity to stabilize E. coli whole-cell membranes. Our results showed that the alanine 123 to serine substitution induces a decrease in chaperone activity in denaturated proteins, and that the tyrosine 107 is required for membrane stabilization. Moreover, this study revealed that the oligomeric structures of proteins with amino acid substitutions do not appear to be modified. Our data strongly suggest that different amino acids are involved in the thermostabilization of proteins and in membrane fluidity regulation and are localized in the alpha-crystallin domain.
乳酸菌片球菌中的小分子热休克蛋白（smHsp）Lo18 可减少蛋白质体外热聚集，并调节天然脂质体的膜流动性。由于缺乏有关 smHsp 对蛋白质和膜表现出稳定作用的方式的信息，促使进行了这项研究。我们在大肠杆菌中表达了三种氨基酸取代的 Lo18 蛋白，以研究它们防止大肠杆菌蛋白质聚集的能力及其稳定大肠杆菌全细胞膜的能力。结果表明，丙氨酸 123 到丝氨酸的取代会降低变性蛋白的伴侣活性，而酪氨酸 107 对于膜稳定是必需的。此外，这项研究表明，具有氨基酸取代的蛋白质的寡聚结构似乎没有改变。我们的数据强烈表明，不同的氨基酸参与蛋白质的热稳定性和膜流动性的调节，并且定位于α-晶状体蛋白结构域。
