Pochapsky Thomas C, Pochapsky Susan S, Ju Tingting, Hoefler Chris, Liang Jue
Department of Chemistry, Brandeis University, MS 015, 415 South Street, Waltham, MA 02454-9110, USA.
J Biomol NMR. 2006 Feb;34(2):117-27. doi: 10.1007/s10858-005-5735-8.
Acireductone dioxygenase (ARD) from Klebsiella ATCC 8724 is a metalloenzyme that is capable of catalyzing different reactions with the same substrates (acireductone and O2) depending upon the metal bound in the active site. A model for the solution structure of the paramagnetic Ni2+-containing ARD has been refined using residual dipolar couplings (RDCs) measured in two media. Additional dihedral restraints based on chemical shift (TALOS) were included in the refinement, and backbone structure in the vicinity of the active site was modeled from a crystallographic structure of the mouse homolog of ARD. The incorporation of residual dipolar couplings into the structural refinement alters the relative orientations of several structural features significantly, and improves local secondary structure determination. Comparisons between the solution structures obtained with and without RDCs are made, and structural similarities and differences between mouse and bacterial enzymes are described. Finally, the biological significance of these differences is considered.
来自肺炎克雷伯菌ATCC 8724的乙醛酸还原酶双加氧酶（ARD）是一种金属酶，根据结合在活性位点的金属不同，它能够催化相同底物（乙醛酸和O2）发生不同反应。利用在两种介质中测量的剩余偶极耦合（RDC）对含顺磁性Ni2+的ARD溶液结构模型进行了优化。基于化学位移（TALOS）的额外二面角约束被纳入优化过程，活性位点附近的主链结构根据ARD小鼠同源物的晶体结构进行建模。将剩余偶极耦合纳入结构优化显著改变了几个结构特征的相对取向，并改善了局部二级结构的确定。对有无RDC时获得的溶液结构进行了比较，并描述了小鼠和细菌酶之间的结构异同。最后，探讨了这些差异的生物学意义。
