Neuhaus D, Nakaseko Y, Schwabe J W, Klug A
MRC Laboratory of Molecular Biology, Cambridge, England.
J Mol Biol. 1992 Nov 20;228(2):637-51. doi: 10.1016/0022-2836(92)90846-c.
This paper describes the detailed three-dimensional structures of two zinc-finger domains from the yeast transcription factor SWI5, calculated using the results of the n.m.r. experiments described in the accompanying paper. The structure of finger 2 is essentially similar to those previously obtained by others for isolated, synthetic single zinc-finger domains in solution, and for the three zinc-finger peptide Zif268 in its crystalline complex with DNA. The N-terminal half of the sequence forms a two-stranded, irregular beta-sheet containing both of the metal-binding cysteine residues, while the remainder of the structure forms a helix. Approximately the first half of this helix is alpha-helical, whereas the C-terminal portion, including the two metal-binding histidine residues, is 3(10) helical. Four invariant hydrophobic residues form a core to the structure. In contrast to all previously described structures of zinc-finger domains, finger 1 has an additional strand in the beta-sheet, formed by residues N-terminal to the formal start of the finger motif. This additional strand plays a role in stabilising the folded form of finger 1, since a two-finger peptide lacking the N-terminal residues showed folded structure in finger 2 but not in finger 1.
本文描述了酵母转录因子SWI5中两个锌指结构域的详细三维结构，该结构是根据随附论文中所述的核磁共振实验结果计算得出的。锌指2的结构与其他人先前在溶液中获得的分离的合成单锌指结构域以及与DNA形成晶体复合物的三锌指肽Zif268的结构基本相似。该序列的N端一半形成一个包含两个金属结合半胱氨酸残基的双链不规则β折叠，而结构的其余部分形成一个螺旋。该螺旋的大约前半部分是α螺旋，而包括两个金属结合组氨酸残基的C端部分是3(10)螺旋。四个不变的疏水残基形成了该结构的核心。与先前描述的所有锌指结构域结构不同，锌指1在β折叠中有一条额外的链，由锌指基序正式起始位点N端的残基形成。这条额外的链在稳定锌指1的折叠形式中起作用，因为缺少N端残基的双指肽在锌指2中呈现折叠结构，而在锌指1中则没有。
