SEGMENTAL FLEXIBILITY OF IMMUNOGLOBULIN-G ANTIBODY MOLECULES IN SOLUTION - A NEW INTERPRETATION
SEGMENTAL FLEXIBILITY OF IMMUNOGLOBULIN-G ANTIBODY MOLECULES IN SOLUTION - A NEW INTERPRETATION
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DOI：
10.1021/bi00527a016
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发表时间：
1981-01-01
期刊：
影响因子：
2.9
通讯作者：
SCHUMAKER, VN
中科院分区：
文献类型：
--
作者：
HANSON, DC;YGUERABIDE, J;SCHUMAKER, VN
提出了一种新的免疫球蛋白片段柔性模型。采用去卷积和光移校正的纳秒荧光光谱技术，重新研究了天然的和轻微还原的抗5-二甲氨基-1-磺酰基(抗丹磺酰基)抗体的柔韧性。本研究使用的兔抗体是从二聚体和其他聚集体中提纯的。原始结果表明，荧光各向异性的衰减涉及2个旋转相关时间。有人认为，短的旋转关联时间vphi.s表示Fab臂在受限角度上的灵活运动，而长的关联时间vphi.L表示分子的整体翻滚。新的数据表明，长的关联时间主要代表FAB片段的运动，而不是整个分子的整体翻滚。这一解释暗示了一种更灵活的免疫球蛋白模型。在溶液中，抗体臂似乎在一个很大的角度上移动，并且不限于33度。正如早期模型中所建议的那样。简单的扩散计算和其他证据表明，.vphi.s可能代表开关多肽或Fab围绕其长轴扭曲的V-模块灵活性，而.vphi.L可能代表Fab臂围绕铰链区的摆动或摆动运动。较快的运动似乎发生在小角度上，而导致各向异性大部分衰减的较慢的摆动或摆动运动似乎受到的限制要小得多。根据所提出的模型解释了免疫球蛋白的生物学功能和铰链二硫键裂解引起的各向异性变化。证明了一种比较随时间变化的和稳态的荧光偏振数据的有效方法。
A new model for the segmental flexibility of IgG is proposed. The flexibility of native and mildly reduced anti-5-(dimethylamino)naphthalene-1-sulfonyl (anti-dansyl) antibody was reexamined by nanosecond fluorescence spectroscopy using deconvolution and lamp-shift corrections. The rabbit antibodies used for this study were purified of dimers and other aggregates. The original results indicated that the decay of fluorescence anisotropy involved 2 rotational correlation times. It was suggested that the short rotational correlation time, .vphi.s, represented a flexible Fab arm motion over a restricted angle and that the long correlation time, .vphi.L, represented global tumbling of the molecule. The new data indicate that the long correlation time primarily represents motions of the Fab segments and not global tumbling of the entire molecule. This interpretation implies a more flexible model for IgG. In solution the antibody arms appear to move over a wide angle and are not restricted to 33.degree. as was suggested in the earlier model. Simple diffusion calculations and other evidence suggest that .vphi.s may represent V-module flexibility about the switch peptides or Fab twisting around its long axis, whereas .vphi.L may represent wagging or wobbling motions of the Fab arms about the hinge region. The faster motions appear to occur over small angles, whereas the slower wagging or wobbling motions responsible for most of the decay of anisotropy appear to be much less restricted. The biological function of IgG and anisotropy changes resulting from hinge disulfide cleavage are interpreted in terms of the proposed model. A useful method for comparison of time-dependent and steady-state fluorescence polarization data is demonstrated.