On the electronic nature of low-barrier hydrogen bonds in enzymatic reactions.
On the electronic nature of low-barrier hydrogen bonds in enzymatic reactions.
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DOI：
10.1073/pnas.95.22.12799
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发表时间：
1998-10
影响因子：
11.1
通讯作者：
B. Schiøtt;B. Iversen;G. Madsen;F. Larsen;T. C. Bruice
中科院分区：
文献类型：
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作者：
B. Schiøtt;B. Iversen;G. Madsen;F. Larsen;T. C. Bruice
结合低温中子和X-射线衍射实验以及以苯甲酰丙酮为模型底物的高水平从头计算，讨论了酶促反应中低垒氢键的电子性质.该分子具有LBHB，因为分子内氢键由具有用于氢转移的小势垒的双阱势描述。从“分子中的原子”的电子密度分析，发现氢原子通过与两个氧的共价键而稳定。实验和理论上都发现了氢键原子上的大原子部分电荷。因此，氢键从共价和长而弱的氢键所发现的正常静电相互作用中获得稳定。基于与具有短强氢键或LBHB的其他系统的比较，提出所有短强和LBHB系统具有类似的氢键区域的电子特征，即氢原子与所讨论的两个杂原子之间的极性共价键。
The electronic nature of low-barrier hydrogen bonds (LBHBs) in enzymatic reactions is discussed based on combined low temperature neutron and x-ray diffraction experiments and on high level ab initio calculations by using the model substrate benzoylacetone. This molecule has a LBHB, as the intramolecular hydrogen bond is described by a double-well potential with a small barrier for hydrogen transfer. From an "atoms in molecules" analysis of the electron density, it is found that the hydrogen atom is stabilized by covalent bonds to both oxygens. Large atomic partial charges on the hydrogen-bonded atoms are found experimentally and theoretically. Therefore, the hydrogen bond gains stabilization from both covalency and from the normal electrostatic interactions found for long, weak hydrogen bonds. Based on comparisons with other systems having short-strong hydrogen bonds or LBHBs, it is proposed that all short-strong and LBHB systems possess similar electronic features of the hydrogen-bonded region, namely polar covalent bonds between the hydrogen atom and both heteroatoms in question.