Amyloid protofibril is highly voluminous and compressible
Amyloid protofibril is highly voluminous and compressible
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DOI：
10.1021/bi700648b
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发表时间：
2007-09-18
期刊：
影响因子：
2.9
通讯作者：
Gekko, Kunihiko
中科院分区：
文献类型：
--
作者：
Akasaka, Kazuyuki;Latif, Abdul Raziq Abdul;Gekko, Kunihiko
我们在这里报告的结果，第一次直接测量的部分体积和可压缩性变化的蛋白质，因为它形成淀粉样蛋白原纤维。我们使用一个高精度的密度计和超声波速度计上的解决方案的本质变性，二硫键缺陷的变体的母鸡溶菌酶，并遵循随时间变化的体积和可压缩性，作为蛋白质自发地形成一个原纤维。我们发现，随着时间的推移，部分比容从0.684增加到0.724 mL中心点g（-1）（增量增量= 0.040 mL中心点g（-1），对应于570 mL中心点（摩尔单体）（-1））和部分比绝热压缩系数从-7.48 × 10（-12）到+1.35 × 10（-12）cm（2）中心点dyn（-1）（Δ β（s）= 8.83 × 10（-12）中心点cm（2）中心点dyn（-1））。结果表明，原纤维是一个高度体积庞大和可压缩的实体，揭示了一个腔丰富，波动的性质淀粉样蛋白原纤维。体积和可压缩性的变化发生在两个阶段，更快的一个前的主要发展的P-结构的原纤维监测CD。
We report here results of the first direct measurement of partial volume and compressibility changes of a protein as it forms an amyloid protofibril. We use a high precision density meter and an ultrasonic velocity meter on a solution of intrinsically denatured, disulfide-deficient variant of hen lysozyme, and follow the time-dependent changes in volume and compressibility, as the protein spontaneously forms a protofibril. We have found a large increase in partial specific volume with time from 0.684 to 0.724 mL center dot g(-1) (Delta upsilon = 0.040 mL center dot g(-1) corresponding to 570 mL center dot(mol monomer)(-1)) and in partial specific adiabatic compressibility coefficient from -7.48 x 10(-12) to + 1.35 x 10(-12) cm(2)center dot dyn(-1) (Delta beta(s) = 8.83 x 10(-12)center dot cm(2)center dot dyn(-1)) as the monomer transforms into a protofibril. The results demonstrate that the protofibril is a highly voluminous and compressible entity, disclosing a cavity-rich, fluctuating nature for the amyloid protofibril. The volume and compressibility changes occur in two phases, the faster one preceding the major development of the P-structure in the protofibril as monitored by CD.