Bullock T L, Clarkson W D, Kent H M, Stewart M
MRC Laboratory of Molecular Biology, Cambridge, UK.
J Mol Biol. 1996 Jul 19;260(3):422-31. doi: 10.1006/jmbi.1996.0411.
Nuclear transport factor 2 (NTF2) facilitates protein transport into the nucleus and interacts with both the small Ras-like GTPase Ran and nucleoporin p62. We have determined the structure of bacterially expressed rat NTF2 at 1.6 angstroms resolution using X-ray crystallography. The NTF2 polypeptide chain forms an alpha + beta barrel that opens at one end to form a distinctive hydrophobic cavity and its fold is homologous to that of scytalone dehydratase. The NTF2 hydrophobic cavity is a candidate for a potential binding site for other proteins involved in nuclear import such as Ran and nucleoporin p62. In addition, the hydrophobic cavity contains a putative catalytic Asp-His pair, which raises the possibility of an unanticipated enzymatic activity of the molecule that may have implications for the molecular mechanism of nuclear protein import.
核转运因子2（NTF2）促进蛋白质转运入细胞核，并与小的Ras样GTP酶Ran和核孔蛋白p62相互作用。我们利用X射线晶体学，以1.6埃的分辨率确定了细菌表达的大鼠NTF2的结构。NTF2多肽链形成一个α + β桶状结构，一端开口形成一个独特的疏水腔，其折叠结构与紫草素脱水酶的折叠结构同源。NTF2疏水腔可能是参与核输入的其他蛋白质（如Ran和核孔蛋白p62）的潜在结合位点。此外，疏水腔含有一对假定的催化性天冬氨酸-组氨酸，这增加了该分子具有意外酶活性的可能性，这可能对核蛋白输入的分子机制有影响。
