Illana B, Zaballos A, Blanco L, Salas M
Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma, Madrid, 28049, Spain.
Virology. 1998 Aug 15;248(1):12-9. doi: 10.1006/viro.1998.9276.
The RGD (Arg-Gly-Asp) motif functions as a recognition site for adhesive proteins responsible for a number of cell-cell interactions. Certain viruses use this sequence as a receptor-binding site by interaction with cellular integrins. To elucidate the role of the RGD sequence of the phi29 terminal protein (TP), seven modified TPs were generated by site-directed mutagenesis. Most of the TP mutants were not efficiently used as primers, leading to a reduction of the TP-dAMP complex formation in the presence of the phi29 TP-DNA template. Moreover, these mutant TPs were poorly deoxyadenylylated by phi29 DNA polymerase in the absence of template. Analysis of primer TP/DNA polymerase complex formation showed that the modified TPs were affected in the formation of the heterodimeric complex. These results indicate that the RGD sequence present in phi29 TP is primarily involved in interaction with the viral DNA polymerase.
RGD（精氨酸-甘氨酸-天冬氨酸）基序作为负责多种细胞间相互作用的黏附蛋白的识别位点发挥作用。某些病毒通过与细胞整合素相互作用，将该序列用作受体结合位点。为了阐明φ29末端蛋白（TP）的RGD序列的作用，通过定点诱变产生了7种修饰的TP。大多数TP突变体不能有效地用作引物，导致在存在φ29 TP-DNA模板的情况下TP-dAMP复合物形成减少。此外，在没有模板的情况下，这些突变的TP被φ29 DNA聚合酶脱氧腺苷酸化的效率很低。引物TP/DNA聚合酶复合物形成的分析表明，修饰的TP在异二聚体复合物的形成中受到影响。这些结果表明，φ29 TP中存在的RGD序列主要参与与病毒DNA聚合酶的相互作用。
