Skubatz Hanna, Orellana Mónica V, Howald William N
NeoPro Labs; Seattle, WA USA.
Institute for Systems Biology; Polar Science Center; Applied Physics Lab; University of Washington; Seattle, WA USA.
Intrinsically Disord Proteins. 2013 Sep 19;1(1):e26372. doi: 10.4161/idp.26372. eCollection 2013 Jan-Dec.
The mode of action of the thermogenic inducers (salicylic acid, aspirin, and 2,6-dihydroxybenzoic acid) in the appendix of the inflorescence is poorly understood. Using ESI-MS and light scattering analysis, we have demonstrated that NAD(P) reductase like protein (RL) is the salicylic acid receptor in the appendix. RL was self-assembled in water into a large unit with a hydrodynamic diameter of 800 nm. In the presence of 1 pM salicylic acid, RL exhibited discontinuous and reversible volume phase transitions. The volume phase changed from 800 to 300 nm diameter and vice versa. RL stayed at each volume phase for ~4-5 min with a fast relaxation time between the 2 phases. ESI-MS analysis of RL extracted from appendices treated with salicylic acid, aspirin, and 2,6-DHBA at a micromolar range demonstrated that these compounds are capable of inducing graded conformational changes that are concentration-dependent. A strong correlation between RL conformations and heat-production induced by salicylic acid was also observed. These preliminary findings reveal structural and conformational roles for RL by which plants regulate their temperature and synchronize their time keeping mechanisms.
花序附属物中热生成诱导剂（水杨酸、阿司匹林和2,6 - 二羟基苯甲酸）的作用模式尚不清楚。通过电喷雾电离质谱（ESI-MS）和光散射分析，我们证明了类NAD(P)还原酶蛋白（RL）是附属物中的水杨酸受体。RL在水中自组装成一个流体动力学直径为800纳米的大单元。在1皮摩尔水杨酸存在的情况下，RL表现出不连续且可逆的体积相变。体积相从直径800纳米变为300纳米，反之亦然。RL在每个体积相停留约4 - 5分钟，两相之间的弛豫时间很快。对在微摩尔范围内用水杨酸、阿司匹林和2,6 - 二羟基苯甲酸处理过的附属物中提取的RL进行ESI-MS分析表明，这些化合物能够诱导浓度依赖性的分级构象变化。还观察到RL构象与水杨酸诱导的产热之间有很强的相关性。这些初步发现揭示了RL在结构和构象方面的作用，植物通过这些作用来调节自身温度并同步其计时机制。
