Abstract：
As plant photoreceptors, phytochromes are capable of detecting red light and far-red light, thereby governing plant growth. All2699 is a photoreceptor found in Nostoc sp. PCC7120 that specifically responds to red light and far-red light. All2699g1g2 is a truncated protein carrying the first and second GAF (cGMP phosphodiesterase/adenylyl cyclase/FhlA) domains of All2699. In this study, we found that, upon exposure to red light, the protein underwent aggregation, resulting in the formation of protein aggregates. Conversely, under far-red light irradiation, these protein aggregates dissociated. We delved into the factors that impact the aggregation of All2699g1g2, focusing on the protein structure. Our findings showed that the GAF2 domain contains a low-complexity (LC) loop region, which plays a crucial role in mediating protein aggregation. Specifically, phenylalanine at position 239 within the LC loop region was identified as a key site for the aggregation process. Furthermore, our research revealed that various factors, including irradiation time, temperature, concentration, NaCl concentration, and pH value, can impact the aggregation of All2699g1g2. The aggregation led to variations in Pfr concentration depending on temperature, NaCl concentration, and pH value. In contrast, ΔLC did not aggregate and therefore lacked responses to these factors. Consequently, the LC loop region of All2699g1g2 extended and enhanced sensory properties.
摘要：
作为植物光感受器，植物色素能够检测红光和远红光，从而控制植物的生长。All2699是在Nostocsp中发现的感光体。PCC7120专门响应红光和远红光。All2699g1g2是携带All2699的第一和第二GAF(cGMP磷酸二酯酶/腺苷酸环化酶/FhlA)结构域的截短蛋白。在这项研究中,我们发现,暴露在红光下，蛋白质发生聚集，导致蛋白质聚集体的形成。相反，在远红光照射下，这些蛋白质聚集体解离。我们深入研究了影响All2699g1g2聚集的因素，重点是蛋白质结构。我们的发现表明，GAF2域包含一个低复杂度(LC)环区域，在介导蛋白质聚集中起着至关重要的作用。具体来说,LC环区域内239位的苯丙氨酸被鉴定为聚集过程的关键位点。此外，我们的研究表明，各种因素，包括辐照时间，温度,浓度,NaCl浓度,和pH值，会影响All2699g1g2的聚集。聚集导致Pfr浓度根据温度而变化，NaCl浓度,和pH值。相比之下,ΔLC没有聚集,因此缺乏对这些因素的响应。因此,All2699g1g2的LC环区延伸并增强了感官特性。
