Crystal structure of a soluble form of the human T cell coreceptor CD8 at 2.6 A resolution
D J Leahy1, R Axel, W A Hendrickson
1Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York 10032.
Abstract:
A secreted fragment of the extracellular portion of human CD8 alpha has been expressed in CHO cells, and a deglycosylated and proteolyzed form of this fragment has been crystallized. We report here the crystal structure of this fragment as refined at 2.6 A resolution. The structure was solved by molecular replacement using a superposition of ten variable domains from immunoglobulin light chains as the search model. Only the N-terminal 114 amino acids of CD8 alpha are visible in the electron density maps. The domain formed by these residues possesses a fold typical of immunoglobulin variable domains and associates to form Fv-like homodimers.
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