13C and 1H nuclear magnetic resonance studies of bradykinin and selected peptide fragments.
13C and 1H nuclear magnetic resonance studies of bradykinin and selected peptide fragments.
复制标题
缓激肽和选定肽片段的 13C 和 1H 核磁共振研究。
DOI：
10.1021/bi00605a003
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发表时间：
1978
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：
R. London;J. Stewart;J. Cann;N. Matwiyoff
完整的/sup 13/C化学位移分配的九肽缓激肽已作出的基础上的pH滴定研究和检查肽片段。先前报道的Arg/sup 9/共振的/sup 13/C位移的滞后效应是pH的函数，并被解释为反映了涉及Arg/sup 1/胍基和Arg/sup 9/羧基的分子内盐桥（Ivanov，V.T.，等人（1975）Bioorg.基姆1，1241; Proc.4th Am. Pept.症状：151)在本研究中没有观察到。脯氨酸碳的化学位移表明，在所有情况下，三个X-Pro肽键的反式构型都非常有利，尽管也可以观察到约占脯氨酸强度10%的次要顺式共振。此外，顺式可逆反式平衡似乎没有显着的pH敏感性。溶剂依赖性的研究（水.. -->..甲醇）的羰基位移是一致的分子内氢键涉及的Ser/sup 6/羰基氧的可能性。初步/sup 1/H核磁共振研究的酰胺质子区的缓激肽和C-末端四肽Ser-Pro-Phe-Arg的报告。在后一种肽中，Phe/sup 8/和更多» Arg/sup 9/酰胺质子共振表现为对应于Ser-Pro键的顺式和反式构型的两组共振。酰胺共振的质子位移的温度依赖性是独立的Ser-Pro键是顺式还是反式，表明任何分子内氢键存在的反式肽是不足以显着降低这个参数。的/sup 13/C自旋-晶格弛豫时间的测量表明快速的内部运动的所有的肽侧链，支持缓激肽存在于溶液中主要是在无序状态的解释。«少
Complete /sup 13/C chemical shift assignments of the nonapeptide bradykinin have been made on the basis of pH titration studies and the examination of peptide fragments. Hysteresis effects previously reported for the /sup 13/C shifts of the Arg/sup 9/ resonances as a function of pH and interpreted to reflect an intramolecular salt bridge involving the Arg/sup 1/ guanido and the Arg/sup 9/ carboxyl (Ivanov, V. T., et al. (1975) Bioorg. Khim. 1, 1241; Proc. 4th Am. Pept. Symp., 151) were not observed in the present study. Chemical shifts of the proline carbons indicate that the trans configuration about the three X-Pro peptide bonds is strongly favored in all cases, although the minor cis resonances accounting for approximately 10% of the proline intensity can also be observed. In addition, there appears to be no significant pH sensitivity of the cis reversible trans equilibria. Studies of the solvent dependence (water ..-->.. methanol) of the carbonyl shifts are consistent with the possibility of an intramolecular hydrogen bond involving the Ser/sup 6/ carbonyl oxygen. Preliminary /sup 1/H nuclear magnetic resonance studies of the amide proton region of bradykinin and the C-terminal tetrapeptide Ser-Pro-Phe-Arg are also reported. In the latter peptide, the Phe/sup 8/ andmore » Arg/sup 9/ amide proton resonances appear as two sets of resonances corresponding to the cis and trans configurations of the Ser-Pro bond. The temperature dependenceof the proton shifts of the amide resonances is independent of whether the Ser-Pro bond is cis or trans, indicating that any intramolecular hydrogen bonding existing only for the trans peptide is insufficient to significantly reduce this parameter. Measurements of the /sup 13/C spin-lattice relaxation times indicate rapid internal motion for all of the peptide side chains, supporting the interpretation that bradykinin exists in solution primarily in a disordered state.« less