CRYSTALLIZATION OF EIAV p26. Zhongmin Jin^1,3, Ashley J. Birkett², Ling Jin², Darrell L. Peterson², Catherine L. Lawson¹. ¹Biology Department, Brookhaven National Laboratory,Upton, NY11973; ²Department of Biochemistry and Molecular Biophysics, Virginia Commonwealth University, Richmond, VA 23298; ³Department of Physics, State University of New York at Stony Brook, Stony Brook, NY11790, USA

We report here the crystallization of the p26 core protein from equine infectious anaemia virus (EIAV), a retrovirus of the Lentiviridae family. EIAV is responsible for causing a chronic, debilitating disease in horses. Infection has been reported worldwide and EIAV is recognized as a livestock pathogen of significent economic importance to the horse industry. There is significent homology between the non-human lentiviruses and HIV-1. The structural study of EIAV gag/core protein will help in understanding the structure of HIV core protein , and in evaluating methods of effective treatment and control of viral infection.

Crystals were grown at room temperature by vapor diffusion with 0.1M Citrate buffer and 10% PEG3300, 15% isopropanol, at pH 6.5. They belong to the space group P6₁22 (or P6₅22) with a = b = 101 Å and c = 158 Å. A complete native data set to 3.6 Å (R_sym = 11 %) has been collected at beamline X12C of National Synchrotron Light Source at Brookhaven National Laboratory. We expect to obtain a higher resolution native, since diffraction from one crystal frozen in liquid propane was observed to 2.8 Å.

The crystal may contain one or two p26 protomers per asymmetric unit. The space group symmetry and cell dimensions suggest that the packing of p26 protomers may be similar to packing of HIV-1 p24 protein in 100 Å diameter fibers (Ehrich et al,1992). EIAV p26 and HIV-1 p24 have 55% sequence homology and 30% sequence identity.