Analysis of gene of Granulicatella adiacens fibronectin-binding protein and application of the gene for clinical diagnosis.

从棘粒霉ATCC 49175T中克隆了一个具有纤维连接蛋白结合能力的基因。DNA序列显示，该基因位于G - adiacens基因组DNA EcoRI-XbaI片段2540bp的第806 ~ 2419位。所得氨基酸序列与乳酸乳球菌2′，3′-环核苷酸2′-磷酸二酯酶（EC 3.1.4.16）同源性达54%。在小鼠中制备了一种针对重组蛋白的抗体，但该抗体不能与G偶联菌的细胞表面结合，这表明该蛋白没有暴露在生物体表面。根据该基因的DNA序列设计了一套PCR引物，并对不同物种的DNA进行扩增。仅从G - adiacens菌株中获得了0.52 kb的PCR产物，而近缘种没有产生产物。来自健康志愿者的牙菌斑临床标本产生单个0.52 kb的产物，G型菌株也是如此。这些结果表明，该PCR引物可用于G邻体的检测和鉴定，用于临床诊断。

A gene encoding a protein with an ability of fibronectin binding was cloned from Granulicatella adiacens ATCC 49175T. DNA sequence revealed that the gene was located from 806 to 2419 on the 2540-bp EcoRI-XbaI fragment from the genomic DNA of G adiacens. The deduced amino acid sequence showed 54% identity to Lactococcus lactis 2', 3' -cyclic nucleotide 2' -phosphodiesterase (EC 3.1.4.16). An antibody specific to the recombinant protein was prepared in mice, but it was not able to bind to the cell surface of G adiacens, suggesting that the protein is not exposed on the surface of the organism. A set of PCR primers was designed according to the DNA sequences of the gene and DNA from various species were subjected to amplification. A 0.52-kb PCR product was yielded only from strains of G adiacens and closely related species produce no product. Clinical specimens of dental plaques from healthy volunteers produced a single 0.52-kb product, as did the type strain G adiacens. These results suggest that the PCR primers are applicable to detection and identification of G adiacens for clinical diagnosis.