Ultraviolet resonance Raman study of side chain electrostatic control of poly-L-lysine conformation.
Ultraviolet resonance Raman study of side chain electrostatic control of poly-L-lysine conformation.
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DOI：
10.1021/jp2005343
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发表时间：
2011-04-14
影响因子：
3.3
通讯作者：
Asher, Sanford A.
中科院分区：
文献类型：
--
作者：
Ma, Lu;Ahmed, Zeeshan;Asher, Sanford A.
我们采用204 nm激发紫外共振拉曼（UVRR）光谱研究侧链静电相互作用在确定聚-L-赖氨酸（PLL）构象中的作用。我们研究了UVRR的pH和离子强度依赖性。PLL UVRR光谱在pH 7.1和11.7之间的pH依赖性不能由两态模型描述，但需要至少一个额外的状态。与pH 7.1和11.7基础光谱拟合的AmIII 3区域揭示了与PPII构象相比2.51-螺旋构象的相对分数的小pH诱导的降低。我们对PLL pH依赖性UVRR光谱进行了二维一般相关分析。异步光谱显示出增强的光谱分辨率。2D异步谱揭示了Cα-H B带和AmII带中的多个成分，其来源尚不清楚。AmIII带与其他带之间的交叉峰表明pH升高诱导了三种新的结构：π-螺旋、α-螺旋和一些转角结构。我们发现，2.5 M NaCl不改变PPII和2.51-螺旋构象之间的平衡，通过筛选侧链静电排斥。结果表明，NaCl不渗透侧链和肽骨架之间的区域。我们还比较了高pH诱导的PLL构象与0.8 M ClO 4 −诱导的PLL构象。这两种条件均诱导α-螺旋样构象。0.8 M ClO 4 −诱导的α-螺旋样构象比pH 12.4时多6%。pH值越高，α-螺旋越长，转角结构越少。
We used 204 nm excitation UV Resonance Raman (UVRR) spectroscopy to examine the role of side chain electrostatic interactions in determining the conformation of poly-L-lysine (PLL). We examined the pH and ionic strength dependence of the UVRR. The pH dependence of PLL UVRR spectra between pH 7.1 and 11.7 cannot be described by a two-state model, but requires at least one additional state. The AmIII3 region fitting with pH 7.1 and 11.7 basis spectra reveals a small pH induced decrease in the relative fraction of the 2.51-helix conformation compared to the PPII conformation. We performed a 2D general correlation analysis on the PLL pH dependence UVRR spectra. The asynchronous spectrum shows enhanced spectral resolution. The 2D asynchronous spectrum reveals multiple components in the Cα-H b band and the AmII band whose origins are unclear. The cross peaks in the 2D asynchronous spectrum between the AmIII band and the other bands reveals that increasing pH induces three new structures: π-helix, α-helix and some turn structure. We find that 2.5 M NaCl does not change the equilibrium between the PPII and 2.51-helix conformations by screening sidechain electrostatic repulsion. The result indicates that NaCl does not penetrate the region between the sidechain and the peptide backbone. We also compared PLL conformations induced by high pH to that induced by 0.8 M ClO4−. Both conditions induce α-helix-like conformations. 0.8 M ClO4− induces 6% more α-helix-like conformations than at pH 12.4. Higher pH gives rise to longer α-helices and less turn structures.
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影响因子：
13.8
作者：
Baldwin, RL;Rose, GD
通讯作者：
Rose, GD
影响因子：
2.9
作者：
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通讯作者：
FINK, AL
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作者：
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通讯作者：
Scheraga, H A
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作者：
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通讯作者：
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影响因子：
3.3
作者：
Dos, Alexandra;Schimming, Volkmar;Limbach, Hans-Heinrich
通讯作者：
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