Conformational study of silk-like peptides containing the calcium-binding sequence from calbindin D9k using 13C CP/MAS NMR spectroscopy.
Conformational study of silk-like peptides containing the calcium-binding sequence from calbindin D9k using 13C CP/MAS NMR spectroscopy.
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DOI：
10.1021/bm050863q
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发表时间：
2006-01
影响因子：
6.2
通讯作者：
T. Asakura;Megumi Hamada;Y. Nakazawa;Sung-Won Ha;D. Knight
中科院分区：
文献类型：
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作者：
T. Asakura;Megumi Hamada;Y. Nakazawa;Sung-Won Ha;D. Knight
钙结合蛋白 D(9k) 的钙结合位点具有螺旋-环-螺旋基序。在这项研究中，螺旋基序被根据几种丝素蛋白的一级序列设计的几个丙氨酸-甘氨酸重复区域所取代。合成的肽用几种有机溶剂处理以修饰 Ala-Gly 重复区域的二级结构。 Ala-Gly 重复区域以及钙结合基序 D(9k)-环 (D(9k)L) 的局部结构通过 (13)C CP/MAS NMR 光谱确定。在合成的含有 D(9k)L 的四种肽中，尽管在肽分子的中心存在 D(9k)L 结构域，但聚 (Ala) 结构域保留了 (A)(12)-D(9k)L 中从 α 螺旋到 β 折叠的构象转变的能力，但在合成的其他模型肽中该结构域的存在对添加的丝状结构域的构象具有显着影响。结果表明，Ala-Gly 重复区的结构可以通过选择有机溶剂和 Ala-Gly 重复区的氨基酸序列来控制，而不破坏 D(9k)L 的二级结构，这表明它可能保留其结合钙离子的能力。
The calcium-binding sites of calbindin D(9k) have a helix-loop-helix motif. In this study, the helix motifs were replaced by several Ala-Gly repeating regions designed on the basis of the primary sequences of several silk fibroins. The synthesized peptides were treated with several organic solvents to modify the secondary structure of the Ala-Gly repeating regions. The local structures of the Ala-Gly repeating regions, as well as the calcium-binding motif, D(9k)-loop (D(9k)L), were determined by (13)C CP/MAS NMR spectroscopy. In the four peptides containing D(9k)L synthesized, the poly(Ala) domains retain the ability to undergo a conformational transition from alpha-helical to beta-sheet in (A)(12)-D(9k)L despite the presence of the D(9k)L domain at the center of the peptide molecule, but the presence of this domain in the other model peptides synthesized has a marked effect on the conformation of the added silk-like domains. The results showed that the structures of the Ala-Gly repeating regions can be controlled by the choice of both the organic solvent and the amino acid sequence of the Ala-Gly repeating regions without disrupting the secondary structure of D(9k)L suggesting that it may retain its ability to bind calcium ions.