Chain length-dependent binding of fatty acid anions to human serum albumin studied by site-directed mutagenesis
Chain length-dependent binding of fatty acid anions to human serum albumin studied by site-directed mutagenesis
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DOI：
10.1016/j.jmb.2006.08.056
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发表时间：
2006-10-27
影响因子：
5.6
通讯作者：
Otagiri, Masaki
中科院分区：
文献类型：
--
作者：
Kragh-Hansen, Ulrich;Watanabe, Hiroshi;Otagiri, Masaki
人血清白蛋白是循环系统中最丰富的蛋白质，其主要功能之一是转运脂肪酸。辛酸，癸酸，月桂酸和肉豆蔻酸的结合进行了研究，通过透析率技术。初级缔合常数随链长增加而增加，但不是线性增加。高亲和力位点的数量也随着链长的增加而增加;辛酸酯和癸酸酯结合到一个这样的位点，而月桂酸酯和肉豆蔻酸酯最有可能结合到两个位点。白蛋白由三个同源螺旋结构域（I-III）组成，其可被细分为两个亚结构域（A和B）。为了获得有关高亲和力位点位置的信息，我们产生了13种在4个不同亚结构域中突变的重组异构体。用这些白蛋白获得的结果与以下模型一致：辛酸酯和癸酸酯结合于亚结构域IIIA中的单个位点，月桂酸酯结合于亚结构域IIIA和IIIB中的位点，而肉豆蔻酸酯结合于亚结构域IB和IIIB中。结果还表明，初级脂肪酸结合对蛋白质其他部分的氨基酸取代敏感。这与遗传白蛋白变体（别白蛋白）的氨基酸取代的效果相反。通常这些位于蛋白质表面的取代对脂肪酸结合没有影响。脂肪酸阴离子与不同的高亲和力位点的结合以及这些位点对蛋白质中其他地方的氨基酸取代（以及可能对其他类型的修饰）的敏感性是可能影响其他配体同时结合的重要因素，例如在用白蛋白结合药物治疗的患者中。(c)2006爱思唯尔有限公司保留所有权利。
Human serum albumin is the most abundant protein in the circulatory system, and one of its principal functions is to transport fatty acids. Binding of octanoate, decanoate, laurate and myristate was studied by a rate-of-dialysis technique. The primary association constants increased, but not linearly, with chain length. The number of high-affinity sites also increased with chain length; octanoate and decanoate bind to one such site, whereas laurate and myristate most probably bind to two sites. Albumin is composed of three homologous helical domains (I-III), which can be subdivided into two subdomains (A and B). For getting information about the positions of the high-affinity sites we produced 13 recombinant isoforms mutated in four different subdomains. Results obtained with these albumins are in accordance with the following model: octanoate and decanoate bind to a single site in subdomain IIIA, laurate binds to sites in subdomains IIIA and IIIB, whereas myristate binds in subdomains IB and IIIB. The results also showed that primary fatty acid binding is sensitive to amino acid substitutions in other parts of the protein. This is in contrast to the effect of amino acid substitutions of genetic albumin variants (alloalbumins). Usually these substitutions, which are situated at the surface of the protein, have no effect on fatty acid binding. Binding of fatty acid anions to different high-affinity sites and the sensitivity of these sites to amino acid substitutions elsewhere in the protein (and perhaps also to other types of modifications) are important factors that could effect simultaneous binding of other ligands, e.g. in patients treated with albumin-binding drugs. (c) 2006 Elsevier Ltd. All rights reserved.