%0 Journal Article
%T Simulation for the primary electronic donor of photosystem in vitro<br>Simulation for the primary electronic donor of photosystem
%A PAN Jie
%A ZHANG Chunxi
%A GONG Yandao
%A LI Liangbi
%A ZHAO Nanming
%A KUANG Tingyun
%A <br>Fig.
%A The
%A absorption
%J 科学通报(英文版)
%D 2000
%I 
%X Histidine coordinated to Chi a is a distinct characteristic of Chl ain vivo. By using histidine analogue of 1-methylimidazole (C4H6N22) and measuring the UV/vis absorption, CD and MCD spectra of the interaction between C4H6N2 and Chl a in CCI4, we have obtained that: (i) In pure CCl4 solvent, Chl a molecule is in five-coordinate state, and two Chl a molecules form an asymmetric compact-dimer with strong coupling interaction. We propose that the two Chl a molecules are connected by two unequally coordinated Mg-O bonds (the two oxygen atoms come from the C=O of C131 keto and C17 ester, respectively); (ii) when the molar ratio of C4H6N2/Chl a is 0.5 or 1 (corresponding to 2Chl a · 1C4H6N2 and 2Chl a · 2C4H6N2, respectively), significant changes have been observed in the absorption, CD and MCD spectra, which indicate that the Chl a remains in dimer form, but the coupling interaction between them reduces greatly. We postulate that C4H6N2 replaces the ligation of C=O of C17 ester and C131 keto to Mg atoms sequentially. The two Chl a molecules linked by two weakly interacted Mg…O bonds form a relaxed-dimer. The structure of the model is essentially similar to that of the primary electronic donor, P680, of photosystem II in high plants and algae.
%K photosynthesis
%K Chl a
%K histidine coordination
%K P680
%K simulation
%K spectroscopy research<br>
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=01BA20E8BA813E1908F3698710BBFEFEE816345F465FEBA5&cid=96E6E851B5104576C2DD9FC1FBCB69EF&jid=DD6615BC9D2CFCE0B6F945E8D5314523&aid=AC8E2479C0F39843&yid=9806D0D4EAA9BED3&vid=94E7F66E6C42FA23&iid=F3090AE9B60B7ED1&sid=FE68044BBD4BDA5F&eid=753F7A67351FADCC&journal_id=1001-6538&journal_name=科学通报(英文版)&referenced_num=0&reference_num=18