Kokke B P, Leroux M R, Candido E P, Boelens W C, de Jong W W
Department of Biochemistry, University of Nijmegen, The Netherlands.
FEBS Lett. 1998 Aug 21;433(3):228-32. doi: 10.1016/s0014-5793(98)00917-x.
Four 12.2-12.6 kDa small heat-shock proteins (sHSPs) of Caenorhabditis elegans are the smallest known members of the sHSP family. They essentially comprise the characteristic C-terminal 'alpha-crystallin domain' of the sHSPs, having a very short N-terminal region, and lacking a C-terminal tail. Recombinant Hsp12.2 and 12.3 are characterized here. Far-UV CD spectra reveal, as for other sHSPs, predominantly a beta-sheet structure. By gel permeation and crosslinking, they are the first sHSPs shown to occur as tetramers, rather than forming the usual large multimeric complexes. Exceptionally, too, both appear devoid of in vitro chaperone-like abilities. This supports the notion that tetramers are the building blocks of sHSP complexes, and that higher multimer formation, mediated through the N-terminal domains, is a prerequisite for chaperone-like activity.
秀丽隐杆线虫的四种12.2 - 12.6 kDa小热休克蛋白（sHSPs）是已知sHSP家族中最小的成员。它们基本上包含sHSPs特征性的C端“α - 晶状体蛋白结构域”，N端区域非常短，且缺少C端尾巴。本文对重组Hsp12.2和12.3进行了表征。远紫外圆二色光谱显示，与其他sHSPs一样，主要为β - 折叠结构。通过凝胶渗透和交联实验表明，它们是首个被证明以四聚体形式存在的sHSPs，而非形成通常的大型多聚体复合物。此外，这两种蛋白在体外均未表现出类似伴侣蛋白的活性。这支持了以下观点：四聚体是sHSP复合物的构建单元，而通过N端结构域介导形成更高阶的多聚体是具有类似伴侣蛋白活性的先决条件。
