Rajarathnam K, Clark-Lewis I, Dewald B, Baggiolini M, Sykes B D
Protein Engineering Network of Centres of Excellence (PENCE) and the Department of Biochemistry, University of Alberta, Edmonton, Canada.
FEBS Lett. 1996 Dec 9;399(1-2):43-6. doi: 10.1016/s0014-5793(96)01277-x.
In order to assess the importance of the buried Glu-38 observed in the structure of interleukin-8, an analog in which Glu-38 was replaced with Ala (E38A analog) was investigated by 1H NMR spectroscopy and neutrophil activation. Detailed analysis of the NMR NOESY data showed that the solution structure of the E38A analog is essentially the same as that for the native protein. Also, the neutrophil elastase activity of the E38A analog was similar to that of the native protein. However, the Gln-8 and Cys-9 amide proton chemical shifts, which are significantly downfield-shifted in the native protein, exhibit more 'normal' values. This observation indicates that in the native protein, Glu-38 side-chain carboxylate interacts with Gln-8 and Cys-9 amide protons. Although the N-terminal residues are critical for function, this interaction is not essential for neutrophil activation.
为了评估白细胞介素-8结构中观察到的埋藏谷氨酸-38的重要性，通过1H核磁共振光谱法和中性粒细胞活化研究了一种将谷氨酸-38替换为丙氨酸的类似物（E38A类似物）。对核磁共振NOESY数据的详细分析表明，E38A类似物的溶液结构与天然蛋白基本相同。此外，E38A类似物的中性粒细胞弹性蛋白酶活性与天然蛋白相似。然而，在天然蛋白中显著向低场位移的谷氨酰胺-8和半胱氨酸-9酰胺质子化学位移表现出更“正常”的值。这一观察结果表明，在天然蛋白中，谷氨酸-38侧链羧酸盐与谷氨酰胺-8和半胱氨酸-9酰胺质子相互作用。虽然N端残基对功能至关重要，但这种相互作用对于中性粒细胞活化并非必不可少。
