Han Gye Won, Elsliger Marc André, Yeates Todd O, Xu Qingping, Murzin Alexey G, Krishna S Sri, Jaroszewski Lukasz, Abdubek Polat, Astakhova Tamara, Axelrod Herbert L, Carlton Dennis, Chen Connie, Chiu Hsiu Ju, Clayton Thomas, Das Debanu, Deller Marc C, Duan Lian, Ernst Dustin, Feuerhelm Julie, Grant Joanna C, Grzechnik Anna, Jin Kevin K, Johnson Hope A, Klock Heath E, Knuth Mark W, Kozbial Piotr, Kumar Abhinav, Lam Winnie W, Marciano David, McMullan Daniel, Miller Mitchell D, Morse Andrew T, Nigoghossian Edward, Okach Linda, Reyes Ron, Rife Christopher L, Sefcovic Natasha, Tien Henry J, Trame Christine B, van den Bedem Henry, Weekes Dana, Hodgson Keith O, Wooley John, Deacon Ashley M, Godzik Adam, Lesley Scott A, Wilson Ian A
Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, USA.
Acta Crystallogr Sect F Struct Biol Cryst Commun. 2010 Oct 1;66(Pt 10):1237-44. doi: 10.1107/S1744309110025534. Epub 2010 Aug 4.
The crystal structure of a putative NTPase, YP_001813558.1 from Exiguobacterium sibiricum 255-15 (PF09934, DUF2166) was determined to 1.78 Å resolution. YP_001813558.1 and its homologs (dimeric dUTPases, MazG proteins and HisE-encoded phosphoribosyl ATP pyrophosphohydrolases) form a superfamily of all-α-helical NTP pyrophosphatases. In dimeric dUTPase-like proteins, a central four-helix bundle forms the active site. However, in YP_001813558.1, an unexpected intertwined swapping of two of the helices that compose the conserved helix bundle results in a `linked dimer' that has not previously been observed for this family. Interestingly, despite this novel mode of dimerization, the metal-binding site for divalent cations, such as magnesium, that are essential for NTPase activity is still conserved. Furthermore, the active-site residues that are involved in sugar binding of the NTPs are also conserved when compared with other α-helical NTPases, but those that recognize the nucleotide bases are not conserved, suggesting a different substrate specificity.
确定了来自西伯利亚栖热菌255-15的假定NTP酶YP_001813558.1（PF09934，DUF2166）的晶体结构，分辨率为1.78 Å。YP_001813558.1及其同源物（二聚体dUTP酶、MazG蛋白和HisE编码的磷酸核糖基ATP焦磷酸水解酶）形成了一个全α螺旋NTP焦磷酸酶超家族。在二聚体dUTP酶样蛋白中，一个中央四螺旋束形成活性位点。然而，在YP_001813558.1中，组成保守螺旋束的两个螺旋发生了意外的相互缠绕交换，形成了一个“连接二聚体”，这在此家族中以前从未观察到。有趣的是，尽管存在这种新颖的二聚化模式，但对于NTP酶活性至关重要的二价阳离子（如镁）的金属结合位点仍然保守。此外，与其他α螺旋NTP酶相比，参与NTP糖结合的活性位点残基也保守，但识别核苷酸碱基的残基不保守，这表明底物特异性不同。
