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Updated: Jul 11, 2026
Purification of a High Molecular Mass Protein in Streptococcus mutans
Published on: September 14, 2019
Protein preparation, crystallization and preliminary X-ray crystallographic analysis of SMU.961 protein from the
Xiong-Zhuo Gao1, Lan-Fen Li, Xiao-Dong Su
1Institute for Nanobiomedical Technology and Membrane Biology, West China Hospital, Sichuan University, Chengdu 610065, Sichuan, People's Republic of China.
Abstract:
The smu.961 gene encodes a putative protein of 183 residues in Streptococcus mutans, a major pathogen in human dental caries. The gene was cloned into expression vector pET28a and expressed in a substantial quantity in Escherichia coli strain BL21 (DE3) with a His tag at its N-terminus. The recombinant protein SMU.961 was purified to homogeneity in a two-step procedure consisting of Ni2+-chelating and size-exclusion chromatography. Crystals suitable for X-ray diffraction were obtained by the hanging-drop vapour-diffusion method and diffracted to 2.9 A resolution at beamline I911-3, MAX-II-lab, Sweden. The crystal belonged to space group C2, with unit-cell parameters a = 98.62, b = 73.73, c = 184.73 A, beta = 98.82 degrees.
