Glycosylation of synthetic peptides breaks helices. Phosphorylation results in distorted structure.
Glycosylation of synthetic peptides breaks helices. Phosphorylation results in distorted structure.
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合成肽的糖基化会破坏螺旋。
DOI：
10.1111/j.1399-3011.1991.tb01529.x
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发表时间：
1991
期刊：
影响因子：
--
通讯作者：
Hollosi,M
中科院分区：
文献类型：
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作者：
OtvosJr,L;Thurin,J;Kollat,E;Urge,L;Mantsch,HH;Hollosi,M
狂犬病病毒糖蛋白的两个糖基化位点位于T细胞表位，即VVEDEGCTNLSGF(VF13，氨基酸29-41)和GKAYTIFNKTLM(GM12，氨基酸312-323)。为了探索翻译后修饰对多肽构象的影响，我们合成了这两个多肽的糖基化和磷酸化版本，并用CD和FT-IR光谱将它们的结构与天然多肽进行了比较。经过修饰，即在ASN上用一个或两个乙酰氨基葡萄糖或葡萄糖残基糖基化或在Ser上磷酸化后，未修饰的多肽的低到中等螺旋度消失，如水-三氟乙醇混合物中的CD测量所示。将一种糖基结合到两种多肽中都会导致高概率的I(III)β-Turn形成，不同的多肽具有几乎相同的光谱。GM12中碳水化合物的延长只略微增强了这一效应。相反，VF13的磷酸化导致了肽骨架的扭曲构象。这种通过糖基化(或磷酸化)改变二级结构的新的和直接的证明可能是决定多肽抗原结构和功能的重要因素。
Two proposed glycosylation sites are located within T cell epitopes of rabies virus glycoprotein, namely VVEDEGCTNLSGF (VF13; amino acids 29‐41) and GKAYTIFNKTLM (GM12; amino acids 312‐323). To explore the effects on peptide conformation due to post‐translational modifications, we synthesized glycosylated and phosphorylated versions of the two peptides and compared their structures with the native peptide using CD and FT‐IR spectroscopy. After the modifications, i.e., glycosylation on Asn with one or twoN‐acetyl‐glucosamine or glucose residues or phosphorylation on Ser, the low to medium degree of helicity of the unmodified peptides disappears as indicated by CD measurements in water‐trifluoroethanol mixtures. Incorporation of one sugar moiety into either peptide resulted with a high probability in a type I (III)β‐turn formation with almost identical spectra for the different peptides. Elongation of the carbohydrate in GM12 only slightly enhanced this effect. In contrast, phosphorylation of VF13 caused distorted conformation of the peptide backbone. This novel and direct demonstration of a change in secondary structure by glycosylation (or phosphorylation) might be an important element in determining peptide antigen structure and function.