Transferrin (Tf) is an iron carrier protein that consists of two lobes, the N- and C-lobes, which can each bind a Fe3+ ion. Tf binds to its receptor (TfR), which mediates iron delivery to cells through an endocytotic pathway. Receptor binding facilitates iron release from the Tf C-lobe, but impedes iron release from the N-lobe. An atomic model of the Tf-TfR complex based on single particle electron microscopy (EM) indicated that receptor binding is indeed likely to hinder opening of the N-lobe, thus interfering with its iron release. The atomic model also suggested that the TfR stalks could form additional contacts with the Tf N-lobes, thus potentially further slowing down its iron release. Here, we show that the TfR stalks are unlikely to make strong interactions with the Tf N-lobes and that the stalks have no effect on iron release from the N-lobes of receptor-bound Tf.
|Original language||English (US)|
|Number of pages||5|
|Journal||Biochemical and Biophysical Research Communications|
|State||Published - Apr 17 2009|
All Science Journal Classification (ASJC) codes
- Molecular Biology
- Cell Biology