Circular dichroism (CD) and small-angle X-ray scattering (SAXS) measurements were made for three xanthan samples, a double helical polysaccharide, in 5 or 10 mM aqueous NaCl after rapid temperature change to investigate the kinetics of the conformational change between the ordered and disordered states. After the rapid heating, the CD signal mainly reflecting the carbonyl groups on the side chains quickly changed (<150 s) while the scattering intensity from SAXS around q (magnitude of the scattering vector) = 1 nm⁻¹ changed more gradually, reflecting the main-chain conformation. The difference between CD and SAXS implies us the intermediate conformation which can be regarded as a loose double helix. The SAXS profile in the rapid cooling process showed that the loose double helical structure was constructed within 150 s, but the CD signal slowly changed with around 2 days to recover the native tight double helix.

在快速温度变化后，在 5 或 10 mM NaCl 水溶液中对三个黄原胶样品（一种双螺旋多糖）进行圆二色性 (CD) 和小角 X 射线散射 (SAXS) 测量，以研究两者之间构象变化的动力学。有序和无序的状态。快速加热后，主要反映侧链上羰基的 CD 信号快速变化（<150 s），而来自 SAXS 的散射强度在q附近（散射矢量的大小）= 1 nm ^-1变化较平缓，反映主链构象。CD和SAXS之间的差异意味着我们可以将中间构象视为松散的双螺旋。快速冷却过程中的 SAXS 剖面显示，松散的双螺旋结构在 150 秒内构建，但 CD 信号在 2 天左右缓慢变化，以恢复天然的紧密双螺旋结构。