The aromatic 1H-NMR spectrum of plasminogen kringle 4. A comparative study of human, porcine and bovine homologs.
The aromatic 1H-NMR spectrum of plasminogen kringle 4. A comparative study of human, porcine and bovine homologs.
复制标题
纤溶酶原三环 4 的芳香 1H-NMR 谱。人、猪和牛同源物的比较研究。
DOI：
10.1111/j.1432-1033.1986.tb09925.x
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发表时间：
1986
期刊：
影响因子：
--
通讯作者：
Llinás,M
中科院分区：
文献类型：
--
作者：
Ramesh,V;Gyenes,M;Patthy,L;Llinás,M
通过300 MHz和600 MHz的二维1H-NMR光谱，将分离的人纤溶酶原kringle 4结构域与牛和猪来源的同源结构（游离和存在配体6-氨基己酸）进行了比较。这三种蛋白质的化学位移相关、自旋回波相关和双量子相关芳香光谱表明，第四个Kringle的球状构象在整个同系物组中保持紧密。直接比较表明，三个保守的色氨酸残基（在位点25，62和72），表现出高度非简并的亚光谱，发现自己在类似的分子内环境。特别是，质子Overhauser实验表明，严格保留了Trp-II（Trp 62或Trp 25）吲哚基团和74位芳环（Tyr 74或Phe 74）之间的紧密空间相互作用。这一特征迫使由Cys 51-Cys 75连接闭合的kringle内环折叠回自身，从而将位点74残基置于Cys 22-Cys 63桥的近端。单残基取代可以明确地将His-I指定为His 3，Tyr-III指定为Tyr 41，Tyr-IV指定为Tyr 74。从该直接证据，与kringle 1光谱和先前报道的Tyr-II（Tyr 50）的化学修饰的比较[Trexler M.，贝尼艾湖，帕蒂·L普勒克N. D. &威廉姆斯R. J. P.（1985）Eur. 152，439-446]，Tyr-I和Tyr-V（后者，在600 MHz时间尺度上的不动环）可以分别归属于Tyr 2和Tyr 9。由于Trp-III先前已在赖氨酸结合位点被分配给Trp 72，因此本研究完成了Kringle 41 H-NMR光谱中12个芳香族自旋系统中的10个的分配;唯一的模糊之处在于Trp-I和Trp-II吲哚自旋系统，它们已完全确定，但仅暂时分别分配给Trp 25和Trp 62。
The isolated kringle 4 domain of human plasminogen has been compared with homologous structures from bovine and porcine sources, both free and in the presence of the ligand 6‐aminohexanoic acid, by two‐dimensional1H‐NMR spectroscopies at 300 MHz and 600 MHz. The chemical‐shift‐correlated, spin‐echo‐correlated, and double‐quantum‐correlated aromatic spectra of the three proteins reveal that the globular conformation of the fourth kringle is closely maintained throughout the set of homologs. Direct comparison shows that the three conserved Trp residues (at sites 25, 62 and 72) which exhibit highly non‐degenerate subspectra, find themselves in similar intramolecular environments. In particular, proton Overhauser experiments reveal that the close steric interaction between the Trp‐II (Trp62or Trp25) indole group and the aromatic ring at site 74 (Tyr74or Phe74) is strictly preserved. This feature forces the kringle inner loop, closed by the Cys51‐Cys75link, to fold back onto itself so as to place the site 74 residue proximal to the Cys22‐Cys63bridge.Single‐residue substitutions enable unambiguous assignments of His‐I to His3, Tyr‐III to Tyr41and Tyr‐IV to Tyr74. From this direct evidence, comparison with the kringle 1 spectrum, and the previously reported chemical modification of Tyr‐II (Tyr50) [Trexler M., Bänyai L., Patthy L., Pluck N. D. & Williams R. J. P. (1985)Eur. J. Biochem. 152, 439–446], Tyr‐I and Tyr‐V (the latter, an immobile ring on the 600‐MHz time scale) could be assigned to Tyr2and Tyr9, respectively. Since Trp‐III has previously been assigned to Trp72at the lysine‐binding site, the present study completes the assignment of 10 out of 12 aromatic spin systems in the kringle 41H‐NMR spectrum; the only ambiguity which remains concerns the Trp‐I and Trp‐II indole spin systems, which are totally identified but as yet only tentatively assigned to Trp25and Trp62, respectively.