Selective modification of Trp19 in β-lactoglobulin by a new diazo fluorescence probe
Selective modification of Trp19 in β-lactoglobulin by a new diazo fluorescence probe
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DOI：
10.1021/pr070284n
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发表时间：
2007-09-01
影响因子：
4.4
通讯作者：
Ma, Huimin
中科院分区：
文献类型：
--
作者：
Bao, Zhijuan;Wang, Shujuan;Ma, Huimin
为了获得蛋白质中色氨酸结构域的局部信息，设计合成了一种新的荧光探针1,7-二（4-羟基-3-甲氧基苯基）-4-重氮-1,6-庚二烯-3,5-二酮，用于色氨酸残基的选择性修饰。探针包括姜黄素荧光基团和重氮标记基团，其光谱特性被表征。重氮基团可被过渡金属配合物如Rh-2(OAc)(4)催化降解，生成活性类羰基铑中间体，该中间体可选择性地与色氨酸残基反应。利用碳烯的分子间反应，重氮姜黄素探针可以修饰β -乳球蛋白的色氨酸残基（Trp19）。此外，Trp19修饰后的二级结构变化较小，但三级结构变化较大，并且Trp19修饰对8-苯胺-1-萘磺酸与视黄醇的结合产生很大影响。这些结果表明，Trp19残基在β -乳球蛋白的结构和稳定性中起着至关重要的作用，对该残基的特异性修饰可能有助于进一步阐明该蛋白的结构和功能之间的关系。
To obtain the local information on the tryptophan domain in a protein, the design and synthesis of a new fluorescent probe, 1,7-bis(4-hydroxy-3-methoxyphenyl)-4-diazo-1,6-heptadiene-3,5-dione, is reported for the Selective modification of tryptophan residues. The probe comprises a curcumin fluorophore and a diazo labeling group, whose spectroscopic properties are characterized. The diazo group may be catalytically degraded by transition metal complexes such as Rh-2(OAc)(4), generating an active rhodium carbenoid intermediate, which can react selectively with tryptophan residues. By the use of the carbene's intermolecular reactions, the tryptophan residue (Trp19) of beta-lactoglobulin may be modified with the diazo curcumin probe. Furthermore, slight secondary but larger tertiary structural changes are detected after Trp19 is modified, and the Trp19 modification produces a great effect on the binding of 8-anilino-1-naphthalenesulfonic acid and retinol. These results indicate that the Trp19 residue plays an essential role in the structure and stability of beta-lactoglobulin, and the specific modification of this residue may have a potential use in further elucidating the relationship between the structure and function of the protein.