Mazur A, Król J E, Skorupska A
Department of General Microbiology, M. Curie-Sklodowska University, Akademicka 19, 20-033 Lublin, Poland.
DNA Seq. 2001 Jul;12(1):1-12. doi: 10.3109/10425170109042046.
Rhizobium leguminosarum bv. trifolii produces an acidic exopolysaccharide (EPS) that plays an important role in symbiotic interaction with clover plants. The sequence of 6.0-kb DNA fragment located upstream of the previously described prsDEorf3 and pssCDE genes involved in exopolysaccharide biosynthesis revealed three new genes designated pssN, pssO and pssP. The predicted protein product of pssP gene shares a significant homology to members of the membrane-periplasmic auxiliary (MPA1) family, that are involved in polymerization of the repeating subunits of EPS. The putative pssN protein product is highly homologous to the family of the outer membrane auxiliary (OMA) proteins engaged in translocation of polysaccharides in bacteria. The PssO did not reveal homology to the known bacterial proteins, but showed characteristic features of outer membrane proteins, and with PssN and PssP, it might be a part of the system involved in polymerization and translocation of EPS across the bacterial membranes.
三叶草根瘤菌三叶草生物变种产生一种酸性胞外多糖（EPS），它在与三叶草植物的共生相互作用中发挥重要作用。位于先前描述的参与胞外多糖生物合成的prsDEorf3和pssCDE基因上游的一个6.0-kb DNA片段的序列揭示了三个新基因，分别命名为pssN、pssO和pssP。pssP基因的预测蛋白质产物与膜-周质辅助（MPA1）家族成员具有显著同源性，该家族成员参与EPS重复亚基的聚合。推测的pssN蛋白质产物与参与细菌多糖转运的外膜辅助（OMA）蛋白家族高度同源。PssO与已知细菌蛋白没有同源性，但显示出外膜蛋白的特征，并且与PssN和PssP一起，它可能是参与EPS跨细菌膜聚合和转运的系统的一部分。
