Solution stability of linear vs. cyclic RGD peptides
Solution stability of linear vs. cyclic RGD peptides
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DOI：
10.1034/j.1399-3011.1999.00052.x
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发表时间：
1999-05-01
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影响因子：
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通讯作者：
Siahaan, TJ
中科院分区：
文献类型：
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作者：
Bogdanowich-Knipp, SJ;Chakrabarti, S;Siahaan, TJ
精氨酸 - 甘氨酸 - 天冬氨酸（RGD）肽含有一个天冬氨酸残基，该残基极易发生化学降解并导致生物活性丧失。我们的假设是，通过二硫键连接使RGD肽环化能够诱导结构刚性，从而防止由天冬氨酸残基介导的降解。在本文中，我们比较了一种线性肽（精氨酸 - 甘氨酸 - 天冬氨酸 - 苯丙氨酸 - 羟基；1）和一种环肽（环 -（1,6）- 乙酰基 - 半胱氨酸 - 精氨酸 - 甘氨酸 - 天冬氨酸 - 苯丙氨酸 - 青霉胺 - 氨基，2）在不同pH值和缓冲液浓度下的溶液稳定性。在50℃下，于pH值2 - 12的缓冲液中研究了这两种肽的分解情况。反相高效液相色谱法被用作确定这两种肽降解命运和途径的主要工具。快原子轰击质谱（FAB - MS）、电喷雾电离质谱（ESI - MS）、基质辅助激光解吸/电离 - 飞行时间（MALDI - TOF）质谱、液相色谱 - 质谱（LC - MS）以及一维和二维核磁共振波谱（NMR）被用于表征肽1和2及其降解产物。此外，通过与标准样品共洗脱来鉴定降解产物。在所有研究的pH值下，这两种肽都呈现准一级动力学。在pH值为7时，环肽2似乎比线性肽1稳定30倍。线性（1）和环肽（2）的降解机制主要涉及天冬氨酸残基。然而，在pH值高于8时，由于二硫键降解，环肽的稳定性急剧下降。随着pH值的升高，这两种肽的降解机制也发生了变化。与线性肽1相比，环肽2稳定性的提高，尤其是在中性pH值下，可能是由于环结构所施加的结构柔性降低。这种刚性将阻止天冬氨酸侧链羧酸将自身定位在合适的位置以攻击肽主链。
Arg-Gly-Asp (RGD) peptides contain an aspartic acid residue that is highly susceptible to chemical degradation and leads to the loss of biological activity. Our hypothesis is that cyclization of RGD peptides via disulphide bond linkage can induce structural rigidity, thereby preventing degradation mediated by the aspartic acid residue. In this paper, we compared the solution stability of a linear peptide (Arg-Gly-Asp-Phe-OH; 1) and a cyclic peptide (cyclo-(1, 6)-Ac-Cys-Arg-Gly-Asp-Phe-Pen-NH2, 2) as a function of pH and buffer concentration. The decomposition of both peptides was studied in buffers ranging from pH 2-12 at 50 degrees C. Reversed-phase HPLC was used as the main tool in determining the degradation Fates and pathways of both peptides. Fast atom bombardment mass spectrometry (FAB-MS), electrospray ionization mass spectrometry (ESI-MS), matrix-assisted laser desorption/ ionization-time of flight (MALDI-TOF) mass spectrometry, liquid chromatography-mass spectrometry (LC-MS), and one- and two-dimensional nuclear magnetic resonance spectroscopy (NMR) were used to characterize peptides 1 and 2 and their degradation products. In addition, co-elution with authentic samples was used to identify degradation products. Both peptides displayed pseudo-first-order kinetics at all pH values studied. The cyclic peptide 2 appeared to be 30-fold more stable than the linear peptide 1 at pH 7. The degradation mechanisms of linear (1) and cyclic (2) peptides primarily involved the aspartic acid residue. However, above pH 8 the stability of the cyclic peptide decreased dramatically due to disulphide bond degradation. Both peptides also exhibited a change in degradation mechanism upon an increase in pH. The increase in stability of cyclic peptide 2 compared to linear peptide 1, especially at neutral pH, may be due to decreased structural flexibility imposed by the ring. This rigidity would prevent the Asp side chain carboxylic acid from orientating itself in the appropriate position for attack on the peptide backbone.