2nyk

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spinqualitylabelsall models 2nyk, resolution 2.10Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

Crystal structure of m157 from mouse cytomegalovirus

Overview

Natural killer (NK) cells express activating and inhibitory receptors, that, in concert, survey cells for proper expression of cell surface major, histocompatibility complex (MHC) class I molecules. The mouse, cytomegalovirus encodes an MHC-like protein, m157, which is the only known, viral antigen to date capable of engaging both activating (Ly49H) and, inhibitory (Ly49I) NK cell receptors. We have determined the 3D structure, of m157 and studied its biochemical and cellular interactions with the, Ly49H and Ly49I receptors. m157 has a characteristic MHC-fold, yet, possesses several unique structural features not found in other MHC class, I-like molecules. m157 does not bind peptides or other small ligands, nor, does it associate with beta(2)-microglobulin. Instead, m157 engages in, extensive intra- and intermolecular interactions within and between its, domains to generate a compact minimal MHC-like molecule. m157's binding, affinity for Ly49I (K(d) approximately 0.2 microM) is significantly higher, than that of classical inhibitory Ly49-MHC interactions. Analysis of viral, escape mutations on m157 that render it resistant to NK killing reveals, that it is likely to be recognized by Ly49H in a binding mode that differs, from Ly49/MHC-I. In addition, Ly49H+ NK cells can efficiently lyse RMA, cells expressing m157, despite the presence of native MHC class I., Collectively, our results show that m157 represents a structurally, divergent form of MHC class I-like proteins that directly engage Ly49, receptors with appreciable affinity in a noncanonical fashion.

About this Structure

2NYK is a Single protein structure of sequence from Murid herpesvirus 1 with as ligand. Full crystallographic information is available from OCA.

Reference

Structural elucidation of the m157 mouse cytomegalovirus ligand for Ly49 natural killer cell receptors., Adams EJ, Juo ZS, Venook RT, Boulanger MJ, Arase H, Lanier LL, Garcia KC, Proc Natl Acad Sci U S A. 2007 Jun 12;104(24):10128-33. Epub 2007 May 30. PMID:17537914

Page seeded by OCA on Wed Jan 23 12:40:51 2008