1H NMR study of the influence of mutation on the interaction of the C-terminus with the active site in heme oxygenase from Neisseria meningitidis: implications for product release.
1H NMR study of the influence of mutation on the interaction of the C-terminus with the active site in heme oxygenase from Neisseria meningitidis: implications for product release.
复制标题
1H NMR 研究突变对脑膜炎奈瑟菌血红素加氧酶 C 末端与活性位点相互作用的影响：对产品释放的影响。
DOI：
10.1021/bi1000867
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发表时间：
2010
期刊：
影响因子：
2.9
通讯作者：
LaMar,GerdN
中科院分区：
文献类型：
--
作者：
Peng,Dungeng;Ma,Li-Hua;Ogura,Hiroshi;Yang,En-Che;Zhang,Xuhong;Yoshida,Tadashi;LaMar,GerdN
来自脑膜炎奈瑟菌（NmHO）的HO具有在晶体结构中未检测到的c端His207、Arg208和His209残基。核磁共振发现c端有序并与活性位点相互作用，并显示c端Arg208 - His209键发生自发裂解，影响产物的脱落率。基于野生型（WT）NmHO配合物的相互作用的初步模型已经提出[Liu， Y., Ma, l.h .]张晓明，张晓明，张晓明，张晓明。（2006）生物化学，38(5):376−378。三种c端截断突变体（Des-His209-、Des-Arg208His209-和Des-His207Arg208His209-NmHO）的静息态、叠氮抑制底物配合物的二维1h NMR数据证实了His207和Arg208之前提出的作用，并揭示了涉及His209羧酸盐和Lys126和Arg208侧链的重要盐桥。His209的缺失导致了c端几何形状的定性保留，但c端与活性位点之间的分离增加。此外，在底物上用甲基取代乙烯基会减少c端与活性位点之间的分离。c末端的扩展模型揭示了一个不太稳定的His207−arg208顺肽键，为其自发切割提供了合理的解释。这种自发切割的速率与c端与活性位点的接近程度有关，这表明更近的相互作用会增加本已较弱的His207 - Arg208肽键的张力。c端结构与体外研究的相关性，以及产品释放的生理功能，进行了讨论。
The HO from the pathogenic bacteriumNeisseria meningitidis,NmHO, possesses C-terminal His207, Arg208, and His209 residues that are undetected in crystal structures. NMR found the C-terminus ordered and interacting with the active site and shown to undergo a spontaneous cleavage of the C-terminal Arg208−His209 bond that affects the product off rate. A preliminary model for the interaction based on the wild-type (WT)NmHO complexes has been presented [Liu, Y., Ma, L.-H., Satterlee, J. D., Zhang, X., Yoshida, T., and La Mar, G. N. (2006)Biochemistry 45, 3875−3886]. Two-dimensional1H NMR data of resting-state, azide-inhibited substrate complexes of the three C-terminal truncation mutants (Des-His209-, Des-Arg208His209-, and Des-His207Arg208His209-NmHO) confirm the previous proposed roles for His207 and Arg208 and reveal important additional salt bridges involving the His209 carboxylate and the side chains of both Lys126 and Arg208. Deletion of His209 leads to a qualitatively retained C-terminal geometry, but with increased separation between the C-terminus and active site. Moreover, replacing vinyls with methyls on the substrate leads to a decrease in the separation between the C-terminus and the active site. The expanded model for the C-terminus reveals a less stable His207−Arg208cispeptide bond, providing a rationalization for its spontaneous cleavage. The rate of this spontaneous cleavage is shown to correlate with the proximity of the C-terminus to the active site, suggesting that the closer interaction leads to increased strain on the already weak His207−Arg208 peptide bond. The relevance of the C-terminus structure for in vitro studies, and the physiological function of product release, is discussed.