Spectroscopic Evidence for Lactam Formation in Terminal Ornithine b2+ and b3+ Fragment Ions
Spectroscopic Evidence for Lactam Formation in Terminal Ornithine b2+ and b3+ Fragment Ions
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末端鸟氨酸 b2 和 b3 碎片离子中内酰胺形成的光谱证据
DOI：
10.1007/s13361-019-02244-0
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发表时间：
2019
影响因子：
3.2
通讯作者：
Poutsma, John C.
中科院分区：
文献类型：
--
作者：
Smith, Zachary M.;Wang, Xiye;Scheerer, Jonathan R.;Martens, Jonathan;Berden, Giel;Oomens, Jos;Steinmetz, Vincent;Somogyi, Arpad;Wysocki, Vicki;Poutsma, John C.
用红外多光子解离作用光谱法研究了含鸟氨酸四肽的AlaOrn b2+和AlaAlaOrn b3+碎片离子。在指纹区（1000-2000 cm-1）中使用红外自由电子激光器在法国奥赛的奥赛中心激光红外实验（克利奥）设施和荷兰奈梅亨的红外实验自由电子激光器（FELIX）设施获得红外光谱。合成了一种新的末端鸟氨酸内酰胺AO+b2+结构用于实验比较，光谱证实AOAA的b2+碎片离子形成内酰胺结构。在B3 LYP/6-31+G（d，p）水平上对实验光谱与标度谐波频率的比较表明，AO+b2+在内酰胺羰基氧或N-末端氮原子上形成一个末端内酰胺质子化。这些异构体的几个低位构象可能在IRMPD解离后被填充。类似地，实验IRMPD光谱与计算光谱的比较表明，AAO+b3+-离子也采用内酰胺结构，再次具有多个不同的质子化位点，在碎裂过程中。这项研究提供了光谱确认内酰胺环化提出的“鸟氨酸效应”，并代表了一个替代的bn+结构的恶唑酮和二酮哌嗪/大环结构最常形成。
Infrared multiple photon dissociation action spectroscopy was performed on the AlaOrn b2+and AlaAlaOrn b3+fragment ions from ornithine-containing tetrapeptides. Infrared spectra were obtained in the fingerprint region (1000–2000 cm−1) using the infrared free electron lasers at the Centre Laser Infrarouge d’Orsay (CLIO) facility in Orsay, France, and the free electron lasers for infrared experiments (FELIX) facility in Nijmegen, the Netherlands. A novel terminal ornithine lactam AO+b2+structure was synthesized for experimental comparison and spectroscopy confirms that the b2+fragment ion from AOAA forms a lactam structure. Comparison of experimental spectra with scaled harmonic frequencies at the B3LYP/6-31+G(d,p) level of theory shows that AO+b2+forms a terminal lactam protonated either on the lactam carbonyl oxygen or the N-terminal nitrogen atom. Several low-lying conformers of these isomers are likely populated following IRMPD dissociation. Similarly, a comparison of the experimental IRMPD spectrum with calculated spectra shows that AAO+b3+-ions also adopt a lactam structure, again with multiple different protonation sites, during fragmentation. This study provides spectroscopic confirmation for the lactam cyclization proposed for the “ornithine effect” and represents an alternative bn+structure to the oxazolone and diketopiperazine/macrocycle structures most often formed.
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DOI：
10.1007/s13361-015-1298-4
发表时间：
2016-03-01
影响因子：
3.2
作者：
Nelson, Carissa R.;Abutokaikah, Maha T.;Bythell, Benjamin J.
通讯作者：
Bythell, Benjamin J.
影响因子：
1.8
作者：
Armentrout, P. B.;Clark, Amy A.
通讯作者：
Clark, Amy A.
影响因子：
1.6
作者：
Martens, Jonathan;Berden, Giel;Oomens, Jos
通讯作者：
Oomens, Jos
IRMPD 光谱显示 AGG 形成恶唑酮 b2 离子。
影响因子：
15
作者：
Yoon,SungHwan;Chamot-Rooke,Julia;Perkins,BrittanyR;Hilderbrand,AmyE;Poutsma,JohnC;Wysocki,VickiH
通讯作者：
Wysocki,VickiH
影响因子：
3.3
作者：
Bythell, Benjamin J.;Csonka, Istvan P.;Suhai, Sandor;Barofsky, Douglas F.;Paizs, Bela
通讯作者：
Paizs, Bela