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Updated: Jul 13, 2026

Combining X-Ray Crystallography with Small Angle X-Ray Scattering to Model Unstructured Regions of Nsa1 from S. Cerevisiae
Published on: January 10, 2018
Crystallization and crystallographic analysis of yeast Sec2p, a guanine nucleotide-exchange factor for the yeast Rab
Yusuke Sato1, Shuya Fukai, Osamu Nureki
1Department of Biological Information, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama-shi, Kanagawa 226-8501, Japan.
Abstract:
Sec2p is a guanine nucleotide-exchange factor (GEF) for the yeast Rab GTPase Sec4p. Sec2p accelerates GDP release from Sec4p and promotes GDP-GTP exchange for Sec4p activation. In order to elucidate this nucleotide-exchange mechanism using X-ray crystallography, three constructs of native Sec2p (Sec2(1-160)p, Sec2(18-160)p and Sec2(31-160)p) and three constructs of selenomethionine-labelled Sec2p [Sec2(31-160)p, Sec2(31-160)p (M115L) and Sec2(31-160)p (M115L, K121M, T142M)] were crystallized. These six crystals diffracted to 8.8, 4.8, 2.6, 4.0, 3.3 and 3.0 A resolution, respectively. The data set from the SeMet-labelled Sec2(31-160)p (M115L, K121M, T142M) crystal was processed for SAD phasing; the crystal belonged to space group P2(1)2(1)2(1), with unit-cell parameters a = 101.9, b = 176.6, c = 181.5 A.
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