Purification, crystallization and preliminary X-ray diffraction analysis of the yeast Sec12Δp protein, a guanine nucleotide-exchange factor involved in vesicle transport

• Published in: Acta crystallographica. Section D, Biological crystallography. Vol. 57; no. 6; pp. 893 - 895
• Main Authors: Dumon-Seignovert, Laurence, Matsumuto, Takashi, Monaco-Malbet, Stéphanie, Tomizaki, Takashi, Sato, Miyuki, Sato, Ken, Nakano, Akihiko, Wakatsuki, Soichi
• Format: Journal Article
• Language: English
• Published: 5 Abbey Square, Chester, Cheshire CH1 2HU, England Munksgaard International Publishers 01.06.2001
• Subjects: GEF proteins; Sec12 protein
• ISSN: 1399-0047; 0907-4449; 1399-0047
• DOI: 10.1107/S0907444901005686

Sec12 is a guanine nucleotide‐exchange factor (GEF) of the GTP‐binding protein Sar1. Its GEF activity on Sar1 makes it a key element in vesicle budding from the endoplasmic reticulum to the Golgi apparatus in yeast. Sec12 is an integral membrane glycoprotein of 70 kDa. A 38.5 kDa N‐cytoplasmic domain (Sec12Δp) has been expressed in Saccharomyces cerevisiae and in Escherichia coli, purified to homogeneity and crystallized. Two crystal forms were obtained. Crystal form I belongs to space group P62/P64, with unit‐cell parameters a = b = 191.7, c = 53.3 Å, γ = 120°, and diffracts to 2.6 Å resolution. Crystal form II belongs to space group P1, with unit‐cell parameters a = 52.6, b = 53.0, c = 116.8 Å, α = 98.0, β = 97.4, γ = 93.4°, and diffracts to 2.0 Å resolution.