Crystallization and preliminary X-ray studies of two serine proteinase inhibitors, BGIA and BGIT from the seeds of bitter gourd

Two serine proteinase inhibitors from seeds of the bitter gourd, BGIA (bitter gourd inhibitor against acidic amino acid-specific proteinase of Streptomyces griseus) and BGIT (bitter gourd trypsin inhibitor), were crystallized for X-ray structure determination. Crystals of BGIA belong to the monoclinic space group C2 with cell dimensions of a = 54.0 Å, b = 23.7 Å, c = 47.9 Å, and β = 105.4°, and diffracted X-ray up to 1.5 Å resolution. Crystals of BGIT belong to the triclinic space group P1 with cell dimensions of a = 22.8 Å, b = 23.5 Å, c = 28.4 Å, α = 93.1°, β = 99.6°, and γ = 101.0°, giving X-ray diffraction of over 1.2 Å resolution. Intensity data of BGIA and BGIT crystals were collected using synchrotron radiation up to 1.7 and 1.4 Å, respectively.