Sims Kurtis L, Schryvers Anthony B
Department of Microbiology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada T2N 4N1.
J Bacteriol. 2003 Apr;185(8):2603-10. doi: 10.1128/JB.185.8.2603-2610.2003.
Transferrin-binding protein B (TbpB) is one component of a bipartite receptor in several gram-negative bacterial species that binds host transferrin and mediates the uptake of iron for growth. Transferrin and TbpB are both bilobed proteins, and the interaction between these proteins seems to involve similar lobe-lobe interactions. Synthetic overlapping peptide libraries representing the N lobe of TbpB from Moraxella catarrhalis were prepared and probed with labeled human transferrin. Transferrin-binding peptides were localized to six different regions of the TbpB N lobe, and reciprocal experiments identified six different regions of the C lobe of transferrin that bound TbpB. Truncations of the N lobe of TbpB that sequentially removed each transferrin-binding determinant were used to probe an overlapping peptide library of the C lobe of human transferrin. The removal of each TbpB N-lobe transferrin-binding determinant resulted in a loss of reactivity with peptides from the synthetic peptide library representing the C lobe of transferrin. Thus, individual peptide-peptide interactions between ligand and receptor were identified. A structural model of human transferrin was used to map surface regions capable of binding to TbpB.
转铁蛋白结合蛋白B（TbpB）是几种革兰氏阴性细菌中双组分受体的一个组成部分，该受体结合宿主转铁蛋白并介导铁的摄取以供生长。转铁蛋白和TbpB都是双叶蛋白，这些蛋白之间的相互作用似乎涉及相似的叶-叶相互作用。制备了代表卡他莫拉菌TbpB N叶的合成重叠肽库，并用标记的人转铁蛋白进行探测。转铁蛋白结合肽定位于TbpB N叶的六个不同区域，反向实验确定了转铁蛋白C叶与TbpB结合的六个不同区域。依次去除每个转铁蛋白结合决定簇的TbpB N叶截短体用于探测人转铁蛋白C叶的重叠肽库。去除每个TbpB N叶转铁蛋白结合决定簇导致与代表转铁蛋白C叶的合成肽库中的肽失去反应性。因此，确定了配体与受体之间的个体肽-肽相互作用。使用人转铁蛋白的结构模型来绘制能够与TbpB结合的表面区域。
