Yang Jianting, Li Qian, Bian Liujiao
Department of Traditional Chinese Medicine, College of Life Science, Northwest University, Xi'an, Shaanxi 710069, P.R. China.
Drug and Equipment Department, Weapon Industry 521 Hospital, Xi'an, Shaanxi 710065, P.R. China.
Exp Ther Med. 2017 Oct;14(4):3288-3298. doi: 10.3892/etm.2017.4853. Epub 2017 Jul 31.
The interaction between TEM-1 β-lactamase and antibiotics is very important in the hydrolysis of antibiotics. In the present study, the recognition and binding of TEM-1 β-lactamase with three β-lactam antibiotics, including penicillin G, cefalexin and cefoxitin, was investigated by fluorescence and ultraviolet-visible absorption spectra in combination with molecular docking in the temperature range of 278-288 K and under simulated physiological conditions. The results demonstrated that the fluorescence emissions of TEM-1 β-lactamase were extinguished by static quenching and the energy of TEM-1 β-lactamase was transferred in a non-radioactive manner. The binding of TEM-1 β-lactamase with the three antibiotics was a spontaneously exothermic process, with binding constants of 1.41×10, 7.81×10 and 5.43×10 at 278 K. Furthermore, binding was driven by enthalpy change and the binding forces between them were mainly hydrogen bonding and Van der Waals forces. A TEM-1 β-lactamase only bound with one antibiotic at a time and the binding capacity between them was closely associated with the functional groups and flexibility in the antibiotics. In addition, a conformational change occurred in the TEM-1 β-lactamases when they bound with the three antibiotics and TEM-1 β-lactamase-antibiotic complexes were formed. The present study provided an insight into the recognition and binding of TEM-1 β-lactamase with β-lactam antibiotics, which may be helpful for designing a novel substrate for TEM-1 β-lactamase and developing novel antibiotics that are resistant to the enzyme.
TEM-1β-内酰胺酶与抗生素之间的相互作用在抗生素水解过程中非常重要。在本研究中,通过荧光光谱和紫外可见吸收光谱,并结合分子对接技术,在278 - 288K温度范围内和模拟生理条件下,研究了TEM-1β-内酰胺酶与三种β-内酰胺抗生素(包括青霉素G、头孢氨苄和头孢西丁)的识别与结合。结果表明,TEM-1β-内酰胺酶的荧光发射通过静态猝灭而熄灭,且TEM-1β-内酰胺酶的能量以非辐射方式转移。TEM-1β-内酰胺酶与这三种抗生素的结合是一个自发的放热过程,在278K时结合常数分别为1.41×10、7.81×10和5.43×10。此外,结合由焓变驱动,它们之间的结合力主要是氢键和范德华力。一个TEM-1β-内酰胺酶一次仅与一种抗生素结合,它们之间的结合能力与抗生素中的官能团和柔韧性密切相关。另外,当TEM-1β-内酰胺酶与这三种抗生素结合时会发生构象变化,并形成TEM-1β-内酰胺酶 - 抗生素复合物。本研究为深入了解TEM-1β-内酰胺酶与β-内酰胺抗生素的识别与结合提供了依据,这可能有助于设计TEM-1β-内酰胺酶的新型底物以及开发对该酶具有抗性的新型抗生素。