CRYSTAL STRUCTURE OF MOLECULAR CHAPERONE, HSC20

分子伴侣在蛋白质的折叠、运输和转运中起着重要作用 以及对压力刺激的反应。 HSC 20是 一种DnaJ型辅伴侣蛋白，编码于最近发现的 操纵子在E. coli中编码DnaK/hsp 70型伴侣蛋白。 没有 已经确定了DnaJ共分子伴侣的结构， N-末端“J”结构域（100个残基）的溶液MNR结构 DnaJ已经揭示了二级结构特征。我们成功地 过表达、纯化和结晶Hsc 20。 因此，Hsc 20可以 提供第一个完整的高分辨率晶体结构， 这类蛋白质。 天然蛋白质的衍射数据具有 使用常规X射线源获得2.6A。 我们准备 通过将半胱氨酸残基引入两个重原子衍生物， 蛋白质诱变 汞标记晶体的晶体太小， 使用我们的X射线源为MIR定相提供数据，我们寻求 利用同步辐射确定更高分辨率的数据 源头

Molecular chaperones play key roles in protein folding, transport and across membranes, and in response to stressful stimuli. Hsc20 is a DnaJ-type cochaperone protein encoded in a recently discovered operon in E. coli which encodes a DnaK/hsp70type chaperone. No structure for a DnaJ co-chaperone has been determined although a solution MNR structure of the N-terminal 'Jdomain (100 residues) of DnaJ has revealed secondary structure features.We succeeded in overexpressing, purifying and crystallizing Hsc20. Thus, Hsc20 could provide the first complete high resolution crystal structure for proteins of this class. Diffraction data for the native protein have been obtained to 2.6A using conventional x-ray sources. We prepared two heavy atom derivatives by introducing cysteine residues into protein mutagenesis. Crystals of Hg-labeled crystals are too small to provide data for MIR phasing using our x-ray source, and we seek to determine higher resolution data using the synchrotron radiation source.