Effects of Temperature and Energy on Stability of Oligomeric Enzyme Probed on Electrospray Ionization Mass Spectrometry
Effects of Temperature and Energy on Stability of Oligomeric Enzyme Probed on Electrospray Ionization Mass Spectrometry作者机构：Institute of Basic Medical Sciences Chinese Academy of Medical Sciences ＆ Peking Union Medical College Beijing 100005 P. R. China
出 版 物：《Chemical Research in Chinese Universities》 (高等学校化学研究（英文版）)
年 卷 期：2008年第24卷第6期
页 面：771-777页
核心收录：
基 金：Supported by National Hi-tech Research and Development Program of China(No.2006AA02Z154) the National Natural Science Foundation of China(No.20675088) and SRF for ROCS, SEM, China
主 题：Electrospray ionization mass spectrometry 3-Deoxy-D-manno-octulosonate 8-phosphate(KDO8P) syn- thase Oligomeric stability
摘 要：Escherichia coli 3-Deoxy-D-manno-octulosonate 8-phosphate（KDO8P） synthase catalyzed the condensation reaction between D-arabinose 5-phosphate（A5P） and phosphoenolpyruvate（PEP） to form KDO8P and inorganic phosphate（Pi）. The noncovalent tetrameric association ofKDO8P synthase was observed and dissociated in gas phase by means of electrospray ionization mass spectrometry under the very ＂soft＂ conditions. The results indicate that PEP-bound enzyme generated abundant tetrameric species as well as monomeric species at the ＂soft＂ conditions, whereas, the unbound enzyme favored the formation of a dimeric species. The mass spectra of the mixture of the enzyme with one of substrates, PEP, and A5P or one of products, KDO8P and Pi show that the complex of the unbound enzyme with PEP or Pi was prone to the formation of a monomeric species, whereas, that of the unbound enzyme with A5P or KDO8P was similar to the unbound enzyme. The intensity of the dimeric species increased with the increase of temperature at a collision voltage of 10 V. Taken together, the results presented here suggest that mass spectrometry will be a powerful tool to explore subtile conformational changes and/or subunit-subunit interactions of multiprotein assembly induced by ligand-binding and/or the changes of environmental conditions.
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