Crystal structure of hevein at 2.8 A resolution.

The three-dimensional structure of hevein, a low molecular weight protein isolated from the latex of Hevea brasiliensis, has been determined by X-ray diffraction at 2.8 A resolution. The protein crystallizes in space group P2(1)2(1)2(1), with lattice constants a = 21.78, b = 31.86, c = 51.12 A. The structure was solved by molecular replacement methods using the domain C of wheat germ agglutinin (WGA) as search model. The positions and individual isotropic temperature factors of the 324 atoms have been refined by the Hendrickson and Konnert restrained refinement procedure. While tight restraints have been maintained on the bonded distances and angles, the R-factor has dropped to 24.1% and an averaged B value of 9.5 A2, using 78% (802) of the total possible number of reflections in the resolution range 5-2.8 A. The tertiary structure is very similar to that of domain C of WGA from residues 3-31.