UNCOUPLED PHOSPHORYLATION AND ACTIVATION IN BACTERIAL CHEMOTAXIS - THE 2.1-ANGSTROM STRUCTURE OF A THREONINE TO ISOLEUCINE MUTANT AT POSITION-87 OF CHEY
UNCOUPLED PHOSPHORYLATION AND ACTIVATION IN BACTERIAL CHEMOTAXIS - THE 2.1-ANGSTROM STRUCTURE OF A THREONINE TO ISOLEUCINE MUTANT AT POSITION-87 OF CHEY
复制标题
DOI：
10.1074/jbc.270.29.17386
复制
发表时间：
1995-07-21
影响因子：
4.8
通讯作者：
VOLZ, K
中科院分区：
文献类型：
--
作者：
GANGULI, S;WANG, H;VOLZ, K
趋化性调节蛋白CheY的87位是反应调节子超家族中高度保守的苏氨酸/丝氨酸残基。一个苏氨酸87异亮氨酸突变体在CheY，其在体内非趋化表型，也被发现是磷酸化在体外。苏氨酸到异亮氨酸CheY突变体的X-射线晶体学结构已经被解析并在2.1埃分辨率下被精细化到15.6%的R因子。与野生型相比，无Mg 2+的CheY结构表明，保留了活性位点结构，但在远离取代的骨架构象中存在显着的局部差异。异亮氨酸侧链的存在还限制了分子中另一个保守残基的旋转构象。在位置106处的酪氨酸。这些结果进一步证明了远离CheY分子磷酸化位点的信号传导表面，并暗示了磷酸化后信号传导事件中的苏氨酸87和其他残基。
Position 87 of the chemotaxis regulatory protein CheY is a highly conserved threonine/serirle residue in the response regulator superfamily. A threonine 87 to isoleucine mutant in CheY, identified by its in vivo non-chemotactic phenotype, was also found to be phosphorylatable in vitro. These properties indicate that this mutant does not undergo activation upon phosphorylation.The x-ray crystallographic structure of the threonine to isoleucine CheY mutant has been solved and refined at 2.1-Angstrom resolution, to an R factor of 15.6%. Comparison with the wild-type, Mg2+-free CheY structure shows that the active site structure is retained, but there are significant localized differences in the backbone conformation distal from the substitution. The presence of the isoleucine side chain also restricts the rotational conformation of another conserved residue in the molecule. tyrosine at position 106. These results provide further evidence for a signaling surface remote from the phosphorylation site of the CheY molecule and implicate threonine 87 and other residues in the post-phosphorylation signaling events.