On the solution conformation of bradykinin and certain fragments.
On the solution conformation of bradykinin and certain fragments.
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关于缓激肽和某些片段的溶液构象。
DOI：
10.1021/bi00648a007
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发表时间：
1976
期刊：
影响因子：
2.9
通讯作者：
N. Matwiyoff
中科院分区：
文献类型：
--
作者：
J. Cann;J. Stewart;R. London;N. Matwiyoff
[D-Pro2]-和[D-Pro3]-缓激肽、选定肽片段和模型化合物的圆二色性（CD）研究。N-acetyl-L-phenylalaninamide，支持了我们之前的结论（Biochemistry 12,3780,1973），即慢激肽221 nm的正CD带是由两个发色团引起的复合带，217 nm的特征带位于n端序列Arg-Pro-Pro的223 nm波段上。结果还表明，Arg-Pro-Pro的223 nm波段与Pro-Pro序列的构型有关，arg - d - pro和Arg-Pro-D-Pro实际上是非对映异构体。据此，对Arg-Pro-Pro的构象进行了更详细的探讨。当温度从27℃左右升高到65℃时，Arg-Pro-Pro发生了构象转变，其特征是δ δ度和δ δ度的大正值，这可以解释为水的结构和，因此，13C核磁共振波谱表明，降低pH值对Arg-Pro-Pro的CD的影响可以解释为在酸性pH下羧基与Pro2羰基氧之间形成氢键，并伴随顺式到反式异构化。
A circular dichroism (CD) study of [D-Pro2]- and [D-Pro3]-bradykinin, selected peptide fragments, and the model compound. N-acetyl-L-phenylalaninamide, support our previous conclusion (Biochemistry 12, 3780, 1973) that the positive 221-nm CD band of bradykinin is a composite of bands due to two chromophores, the 217-nm band characteristic of the Phe residues overlying the 223-nm band of the N-terminal sequence, Arg-Pro-Pro. The results also indicate that the 223-nm band of Arg-Pro-Pro is associated with the configuration of the Pro-Pro sequence, Arg-D-Pro-Pro and Arg-Pro-D-Pro virtually being diastereoisomers. Accordingly, the conformation of Arg-Pro-Pro was probed in further detail. Upon increasing the temperature from about 27 to 65 degrees C, Arg-Pro-Pro undergoes a conformational transition characterized by large positive values of deltaHdegrees and deltaSdegrees, which is interpreted to mean that the structure of water and, thus, solute-solvent interactions play a dominant role in determining the conformation of the peptide 13C nuclear magnetic resonance spectroscopy indicates that the effect of lowering the pH on the CD of Arg-Pro-Pro is explicable in terms of hydrogen-bond formation between the carboxyl group and Pro2 carbonyl oxygen at acid pH with concomitant cis to trans isomerization.