CRYSTAL STRUCTURE OF SMALL MOLECULAR WEIGHT CHEMOKINE

University Of Calif-Los Alamos Nat Lab, Los Alamos NM

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Abstract

The SIR provided (Q-Te-Met; I g L-Telluromethionine; 1.5g Two TeMet proteins have been produced and purified with the first shipment of (Q-Te-Met received from the SIR. As mentioned by Pete Silks of the SIR, the expression levels of these proteins was drastically reduced, as compared with normal Met proteins. The second protein, a small-molecular weight chemokine, yielded several mg of pure protein. It was impossible to determine directly the of tellurium, since analysis by mass spectrometry requires that the proteins be in a very acidic buffer, which would destroy the very thing we would like to measure. Amino acid sequencing revealed the presence of normal methionine at the N-terminal. The absence of this methionine at position 19 (which should be Met) indicates incorporation of TeMet at this position. There is a 3rd methionine in the protein, but we did not sequence that far. I have obtained small crystals of the chemokine protein. A request for synchrotron time has been made at the ESRF. These crystals will be used to phase our crystallographic data.