State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, PR China.
FEBS Lett. 2013 Jul 11;587(14):2232-40. doi: 10.1016/j.febslet.2013.05.052. Epub 2013 Jun 4.
We prepared eight mutants (D76P, D76N, D84P, D84N, D102P, D102N, D150P and D150N) to investigate the functions of residues Asp76, 84, 102 and 150 in human arsenic(III) methyltransferase (hAS3MT) interacting with the S-adenosylmethionine (SAM)-binding. The affinity of all the mutants for SAM were weakened. All the mutants except for D150N completely lost their methylation activities. Residues Asp76, 84, 102 and 150 greatly influenced hAS3MT catalytic activity via affecting SAM-binding or methyl transfer. Asp76 and 84 were located in the SAM-binding pocket, and Asp102 significantly affected SAM-binding via forming hydrogen bonds with SAM.
我们制备了 8 种突变体（D76P、D76N、D84P、D84N、D102P、D102N、D150P 和 D150N），以研究残基 Asp76、84、102 和 150 在与人砷（III）甲基转移酶（hAS3MT）与 S-腺苷甲硫氨酸（SAM）结合相互作用中的功能。所有突变体与 SAM 的亲和力都减弱了。除了 D150N 之外，所有突变体完全失去了甲基化活性。残基 Asp76、84、102 和 150 通过影响 SAM 结合或甲基转移极大地影响 hAS3MT 的催化活性。Asp76 和 84 位于 SAM 结合口袋中，而 Asp102 通过与 SAM 形成氢键显著影响 SAM 结合。
