Kamal Neel, Chowdhury Shantanu, Madan Taruna, Sharma Deepak, Attreyi M, Haq Wahajul, Katti Seturam Bandacharya, Kumar Anil, Sarma P Usha
Institute of Genomics and Integrative Biology, Mall Road, Delhi, India.
Mol Cell Biochem. 2005 Jul;275(1-2):223-31. doi: 10.1007/s11010-005-2056-x.
The role of tryptophan (Trp17) in immunoreactivity of P1, the diagnostically relevant peptide from a major allergen/antigen of Aspergillus fumigatus, was evaluated by chemically modifying tryptophanyl residue of P1. In BIAcore kinetic studies, unmodified P1 showed a 100-fold higher binding with ABPA (Allergic Bronchopulmonary Aspergillosis) patients' IgG [KD (equilibrium dissociation constant) = 2.74 e(-8) +/- 0.13 M] than the controls' IgG (KD = 2.97 e(-6) +/- 0.14 M), whereas chemically-modified P1 showed similar binding [KD patients' IgG = 3.25 e(-7) +/- 0.16 M, KD controls' IgG = 3.86 e(-7) +/- 0.19 M] indicating loss of specific immunoreactivity of P1 on tryptophan modification. Modified P1 showed loss of specific binding to IgE and IgG antibodies of ABPA patients in ELISA (Enzyme-Linked Immunosorbent Assay). The study infers that tryptophan residue (Trp17) is essential for immunoreactivity of P1.
通过化学修饰烟曲霉主要变应原/抗原的诊断相关肽P1中的色氨酸残基，评估了色氨酸（Trp17）在P1免疫反应性中的作用。在BIAcore动力学研究中，未修饰的P1与变应性支气管肺曲霉病（ABPA）患者的IgG的结合力（平衡解离常数KD = 2.74×10⁻⁸±0.13 M）比对照IgG（KD = 2.97×10⁻⁶±0.14 M）高100倍，而化学修饰的P1显示出相似的结合力（患者IgG的KD = 3.25×10⁻⁷±0.16 M，对照IgG的KD = 3.86×10⁻⁷±0.19 M），这表明P1经色氨酸修饰后特异性免疫反应性丧失。在酶联免疫吸附测定（ELISA）中，修饰后的P1显示出与ABPA患者的IgE和IgG抗体的特异性结合丧失。该研究推断色氨酸残基（Trp17）对P1的免疫反应性至关重要。
