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首页> 外文期刊>Polyhedron: The International Journal for Inorganic and Organometallic Chemistry >Palladium(II) complexes of oligopeptides containing aspartyl and glutamyl residues
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Palladium(II) complexes of oligopeptides containing aspartyl and glutamyl residues

机译：含有天冬氨酰和谷氨酰基残基的寡肽的钯（II）配合物

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摘要

Potentiometric and 1H NMR spectroscopic measurements have been performed on palladium(II) complexes of di-, tri- and tetra-peptides containing aspartyl and glutamyl residues including AspAla, AlaAsp, AspAsp, AspAspAsp, GluGluGlu, GlyAspGly, AspAspAspAsp and GlyGlyAspGly. In the case of dipeptides the coordination modes are basically determined by the peptide backbone. The presence of the extra b-carboxylate residues does not result in new binding modes but these functions may slightly affect the thermodynamic stability of several species. For tripeptides the most important findings are connected to the governing role of the β-carboxylate group of internal aspartyl residues but similar effects were not observed for the peptides containing glutamic acid. Aspartic acid in the second position of a tripeptide (Xaa-Asp-Yaa sequence) promotes the binding of the preceding and prevents deprotonation and coordination of subsequent amide functions. In the case of tetrapeptides, the aspartyl residues present in the tird position from the N-terminus (Xaa-Yaa-Asp-Zaa sequence) have the most pronounced effect on complex formation. In this case, the (NH_2, N-, N-, β-COO-)-coordination is the major binding mode and the species [PdH-_2L] can exist in a wide pH range. The enhanced stability of these complexes was explained by the conformational changes of the coordinated ligands.
机译：已对含有天冬氨酰和谷氨酰基残基的二肽，三肽和四肽的钯（II）复合物（包括AspAla，AlaAsp，AspAsp，AspAspAspAsp，GluGluGlu，GlyAspGly，AspAspAspAspAsp和GlyAly）进行了电位和1H NMR光谱测量。在二肽的情况下，配位模式基本上由肽主链决定。额外的b-羧酸根残基的存在不会导致新的结合模式，但是这些功能可能会稍微影响几种物质的热力学稳定性。对于三肽，最重要的发现与内部天冬氨酰残基的β-羧酸根基团的支配作用有关，但对于含谷氨酸的肽未观察到类似的作用。三肽（Xaa-Asp-Yaa序列）的第二个位置的天冬氨酸可促进前述结合，并防止去质子化和随后酰胺功能的配位。在四肽的情况下，存在于N末端第三位的天冬氨酰残基（Xaa-Yaa-Asp-Zaa序列）对复合物的形成有最明显的影响。在这种情况下，（NH_2，N-，N-，β-COO-）配位是主要的结合方式，[PdH-_2L]可以在较宽的pH范围内存在。这些配体的增强的稳定性由配体的构象变化解释。

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