The crystal structure and biological function of leukemia inhibitory factor: implications for receptor binding.
Robinson RC., Grey LM., Staunton D., Vankelecom H., Vernallis AB., Moreau JF., Stuart DI., Heath JK., Jones EY.
The structure of murine leukemia inhibitory factor (LIF) has been determined by X-ray crystallography at 2.0 A resolution. The main chain fold conforms to the four alpha-helix bundle topology previously observed for several members of the hematopoietic cytokine family. Of these, LIF shows closest structural homology to granulocyte colony-stimulating factor and growth hormone (GH). Sequence alignments for the functionally related molecules oncostatin M and ciliary neurotrophic factor, when mapped to the LIF structure, indicate regions of conserved surface character. Analysis of the biological function and receptor specificity of a series of human-mouse LIF chimeras implicate two regions of receptor interaction that are located in the fourth helix and the preceding loop. A model for receptor binding based on the structure of the GH ligand-receptor complex requires additional, novel features to account for these data.