Kenne Adela N, Kim Sunmin, Park SangYoun
School of Systems Biomedical Science, Soongsil University, Seoul 06978, Republic of Korea.
School of Systems Biomedical Science, Soongsil University, Seoul 06978, Republic of Korea.
Int J Biol Macromol. 2016 Jun;87:317-21. doi: 10.1016/j.ijbiomac.2016.02.071. Epub 2016 Mar 2.
Sulfur incorporations both in the biosynthesis of sulfur-containing cofactors and in the sulfur-modifications of certain tRNAs are all mediated by the sulfur initially delivered from the cysteine desulfurases. Sulfur generated as persulfide from cysteine is transferred to the sulfur acceptor protein to further allow delivery to the required steps within an enzymatic process. CsdA which is one of the three cysteine desulfurases identified in Escherichia coli transfers sulfur to the non Fe-S sulfur-acceptor CsdE, however, the consequence of CsdE accepted sulfur is mostly unknown. In this study, we report the 2.4Å structure of free CsdE determined using X-ray crystallography, and compare the structure with the CsdE structure determined using NMR and also CsdE within the crystal CsdA-CsdE complex. Further analysis suggests that the positive electrostatic potential surfaces of CsdE may mediate interaction with a yet unidentified protein or possibly tRNA to deliver sulfur.
在含硫辅因子的生物合成以及某些tRNA的硫修饰过程中，硫的掺入均由最初从半胱氨酸脱硫酶传递而来的硫介导。从半胱氨酸生成的过硫化物形式的硫被转移至硫受体蛋白，进而在酶促过程中传递至所需步骤。CsdA是在大肠杆菌中鉴定出的三种半胱氨酸脱硫酶之一，它将硫转移至非铁硫硫受体CsdE，然而，CsdE接受硫后的结果大多未知。在本研究中，我们报告了利用X射线晶体学测定的游离CsdE的2.4Å结构，并将该结构与利用核磁共振测定的CsdE结构以及晶体CsdA-CsdE复合物中的CsdE结构进行比较。进一步分析表明，CsdE带正电的静电势表面可能介导与尚未鉴定的蛋白质或可能的tRNA的相互作用以传递硫。
