Zhao Y, Sane D C
Department of Medicine, Duke University Medical Center, Durham NC 27710.
Biochem Biophys Res Commun. 1993 Apr 30;192(2):575-82. doi: 10.1006/bbrc.1993.1454.
The cell attachment activity of vitronectin has been ascribed to an Arg-Gly-Asp (RGD) sequence near the amino terminus. To verify the importance of the RGD sequence for cell binding, we created RAD and RGE vitronectin mutants and also deleted either the somatomedin B (delta S-rVN) or heparin (delta H-rVN) binding domains. These mutants were expressed as fusion proteins, purified using Ni+2 affinity chromatography, and assayed for cell attachment. EAhy.926 cells bound equally well to wild-type, delta S-rVN, and to delta H-rVN, but binding to RAD-rVN and RGE-rVN was inhibited by more than 90%. We therefore conclude that the RGD sequence of vitronectin is the most important cell recognition site and that neither the somatomedin B nor heparin domains contribute significantly to the cell adhesive activity of vitronectin.
玻连蛋白的细胞黏附活性归因于氨基末端附近的精氨酸 - 甘氨酸 - 天冬氨酸（RGD）序列。为了验证RGD序列对细胞结合的重要性，我们构建了RAD和RGE玻连蛋白突变体，还删除了生长调节素B（δS - rVN）或肝素（δH - rVN）结合结构域。这些突变体作为融合蛋白表达，通过镍离子亲和层析纯化，并检测细胞黏附情况。EAhy.926细胞与野生型、δS - rVN和δH - rVN的结合情况相同，但与RAD - rVN和RGE - rVN的结合被抑制了90%以上。因此，我们得出结论，玻连蛋白的RGD序列是最重要的细胞识别位点，生长调节素B和肝素结构域对玻连蛋白的细胞黏附活性均无显著贡献。
