Khamrui Susmita, Biswas Maitree, Sen Udayaditya, Dasgupta Jhimli
Crystallography and Molecular Biology Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700 064, India.
Acta Crystallogr Sect F Struct Biol Cryst Commun. 2010 Aug 1;66(Pt 8):944-7. doi: 10.1107/S1744309110022797. Epub 2010 Jul 29.
Vibrio cholerae is the aetiological agent of the severe diarrhoeal disease cholera. This highly motile organism uses the processes of motility and chemotaxis to travel and colonize the intestinal epithelium. Chemotaxis in V. cholerae is far more complex than that in Escherichia coli or Salmonella typhimurium, with multiple paralogues of various chemotaxis genes. In contrast to the single copy of the chemotaxis response-regulator protein CheY in E. coli, V. cholerae contains four CheYs (CheY1-CheY4), of which CheY3 is primarily responsible for interacting with the flagellar motor protein FliM, which is one of the major constituents of the ;switch complex' in the flagellar motor. This interaction is the key step that controls flagellar rotation in response to environmental stimuli. CheY3 has been cloned, overexpressed and purified by Ni-NTA affinity chromatography followed by gel filtration. Crystals of CheY3 were grown in space group R3, with a calculated Matthews coefficient of 2.33 A3 Da(-1) (47% solvent content) assuming the presence of one molecule per asymmetric unit.
霍乱弧菌是严重腹泻疾病霍乱的病原体。这种高度运动的生物体利用运动和趋化作用过程在肠道上皮中移动并定殖。霍乱弧菌中的趋化作用比大肠杆菌或鼠伤寒沙门氏菌中的趋化作用复杂得多，各种趋化基因存在多个旁系同源物。与大肠杆菌中趋化反应调节蛋白CheY的单拷贝不同，霍乱弧菌含有四种CheY（CheY1-CheY4），其中CheY3主要负责与鞭毛运动蛋白FliM相互作用，FliM是鞭毛运动中“开关复合体”的主要成分之一。这种相互作用是响应环境刺激控制鞭毛旋转的关键步骤。CheY3已通过镍-亚氨基三乙酸亲和层析随后进行凝胶过滤进行克隆、过表达和纯化。CheY3晶体在空间群R3中生长，假设每个不对称单元存在一个分子，计算得到的马修斯系数为2.33 Å3 Da-1（溶剂含量47%）。
