Identification of small proteins in nodules of Robinia pseudoacacia

Robinia pseudoacacia L. (black locust) is capable of nitrogen fixation in association with rhizobia. Global transcriptional analysis in Robinia pseudoacacia nodules revealed the presence of three highly abundant small transcripts that may encode small proteins. The high number of proline and glycine residues is the most interesting feature of these proteins. A gelfree bottom up proteomics approach was used for the direct detection of the predicted small proteins. Crude protein extracts were obtained from nodules of wild Robinia (Robinia pseudoacacia). The endoproteases AspN and α-lytic protease were selected for protein digestion. One of these small proteins has been experimentally identified by mass spectrometry.

刺槐（Robinia pseudoacacia L.，black locust）可与根瘤菌共生实现固氮功能。对刺槐根瘤开展的全局转录组分析显示，存在3种丰度极高的小转录本，其可能编码小蛋白。这类蛋白最显著的特征是含有大量脯氨酸与甘氨酸残基。研究采用无凝胶自下而上蛋白质组学方法对预测的小蛋白进行直接检测：实验所用粗蛋白提取物提取自野生刺槐的根瘤，选用内切蛋白酶AspN与α-裂解蛋白酶进行蛋白酶解。其中一种小蛋白已通过质谱法完成实验鉴定。