Tarkkanen A M, Westerlund-Wikström B, Erkkilä L, Korhonen T K
Department of Biosciences, University of Helsinki, Finland.
Infect Immun. 1998 May;66(5):2356-61. doi: 10.1128/IAI.66.5.2356-2361.1998.
The adhesive minor protein MrkD of the type 3 fimbria of Klebsiella pneumoniae was expressed and purified from Escherichia coli as a fusion protein with an N-terminal polyhistidine tail. Polyclonal antibodies raised against MrkD specifically recognized the MrkD peptide in Western blots of fimbrial preparations. Immunoelectron microscopic analyses showed that the anti-MrkD immunoglobulins bound to the tip of the plasmid-encoded variant of the type 3 fimbria of K. pneumoniae, whereas no binding to the chromosomally encoded MrkD-deficient type 3 fimbrial variant of K. pneumoniae was detected. Immunoglobulins from an antiserum raised against purified type 3 fimbrial filaments bound laterally to both type 3 fimbrial variants. The anti-MrkD antibodies also bound to the tip of a papG deletion derivative of the E. coli P fimbria complemented with mrkD, indicating that MrkD structurally complements a PapG mutation in the P fimbria of E. coli.
肺炎克雷伯菌3型菌毛的黏附性次要蛋白MrkD在大肠杆菌中表达并作为带有N端多聚组氨酸尾的融合蛋白进行纯化。针对MrkD产生的多克隆抗体在菌毛制剂的蛋白质免疫印迹中能特异性识别MrkD肽段。免疫电镜分析表明，抗MrkD免疫球蛋白结合于肺炎克雷伯菌3型菌毛质粒编码变体的尖端，而未检测到与肺炎克雷伯菌染色体编码的MrkD缺陷型3型菌毛变体的结合。针对纯化的3型菌毛丝产生的抗血清中的免疫球蛋白能侧向结合两种3型菌毛变体。抗MrkD抗体也能结合用mrkD互补的大肠杆菌P菌毛的papG缺失衍生物的尖端，这表明MrkD在结构上能弥补大肠杆菌P菌毛中PapG的突变。
