The binding spectra of carp C3 isotypes against natural targets independent of the binding specificity of their thioester
The binding spectra of carp C3 isotypes against natural targets independent of the binding specificity of their thioester
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DOI：
10.1016/j.dci.2012.03.004
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发表时间：
2012-09-01
影响因子：
2.9
通讯作者：
Nakao, Miki
中科院分区：
文献类型：
--
作者：
Ichiki, Satoko;Kato-Unoki, Yoko;Nakao, Miki
补体的中心成分C3在脊椎动物和一些无脊椎动物的先天免疫防御中起着多方面的作用。该组分的一个显著分子特征是链内硫酯位点，其使C3能够共价结合其靶标。据报道，硫酯与羟基或氨基的结合优先性主要由人C3中1126位催化性组氨酸残基的存在或不存在来确定。在硬骨鱼中，除了常见的His型C3外，还发现了一种独特的C3（非His型）。这些不同的C3同种型可提供归因于其硫酯的不同结合特异性的靶标结合的多样性。在本研究中，我们研究了催化组氨酸与鲤鱼的两个主要C3同种型对各种模型和自然目标的结合光谱的假设相关性。结果表明，非His型C3，而不是His型C3，具有更广泛的结合谱，尽管其硫酯的结合特异性限于氨基。因此，假设C3同种型的结合谱不是由硫酯的结合特异性限定的，而是更多地受到激活补体的微生物相关分子模式的差异的影响。总体而言，目前的数据表明，非His型C3在鱼类防御系统中对细菌感染起着重要作用。(C)2012爱思唯尔有限公司出版
The central component of complement, C3, plays a versatile role in innate immune defense of vertebrates and some invertebrates. A notable molecular characteristic of this component is an intra-chain thioester site that enables C3 to bind covalently to its target. It has been reported that the binding preference of the thioester to hydroxyl or amino groups is primarily defined by presence or absence of the catalytic histidine residue at position 1126 in human C3. In teleosts, a unique C3 (non-His type) has been found, in addition to the common His type C3. These distinct C3 isoforms may provide diversity in the target-binding attributable to the different binding specificities of their thioesters. In the present study, we examine the hypothesized correlation of the catalytic histidine with the binding spectra of two major C3 isotypes of carp towards various model and natural targets. The results reveal that non-His type C3, rather than His type C3, has a wider range of binding spectrum, despite the binding specificity of its thioester being limited to amino groups. It is therefore hypothesized that the binding spectra of C3 isotypes are not defined by the binding specificity of the thioester but is more affected by differences in microbe-associated molecular patterns that activate complement. Overall, the present data imply that non-His type C3 plays a significant role against bacterial infections in the fish defense system. (C) 2012 Published by Elsevier Ltd.