van Rijk A F, van den Hurk M J, Renkema W, Boelens W C, de Jong W W, Bloemendal H
Department of Biochemistry, University of Nijmegen, The Netherlands.
FEBS Lett. 2000 Sep 1;480(2-3):79-83. doi: 10.1016/s0014-5793(00)01908-6.
alphaA-Crystallin, a small heat shock protein with chaperone-like activity, forms dynamic multimeric complexes. Recently we described the spontaneous generation of a mutant protein (super alphaA-crystallin) by exon duplication arisen via exon shuffling confirming a classic hypothesis by Gilbert [Nature 271 (1978) 501]. Comparison of super alphaA-crystallin, which is viable in a mouse skeletal muscle cell line, with normal alphaA-crystallin shows that it has diminished thermostability, increased exposure of hydrophobic patches, a larger complex size and lost its chaperone activity. However, super alphaA-crystallin subunits exchange as readily between complexes as does normal alphaA-crystallin. These data indicate that chaperone-like activity may vanish independent of subunit hydrophobicity and exchangeability.
αA-晶体蛋白是一种具有伴侣样活性的小热休克蛋白，可形成动态多聚体复合物。最近，我们描述了通过外显子重排产生的外显子重复自发产生的一种突变蛋白（超级αA-晶体蛋白），证实了吉尔伯特的一个经典假说[《自然》271 (1978) 501]。在小鼠骨骼肌细胞系中可存活的超级αA-晶体蛋白与正常αA-晶体蛋白的比较表明，它的热稳定性降低，疏水斑块暴露增加，复合物尺寸更大且失去了伴侣活性。然而，超级αA-晶体蛋白亚基在复合物之间的交换与正常αA-晶体蛋白一样容易。这些数据表明，伴侣样活性可能会独立于亚基疏水性和可交换性而消失。
