Expression and purification of mouse peptide ESP4 in Escherichia coli.
Pheromones are species-specific chemical signals that regulate a wide range of social and sexual behaviors in many animals. In mice, the male-specific peptide ESP1 (exocrine gland-secreting peptide 1) is secreted into tear fluids and enhances female sexual receptive behavior. ESP1 belongs to the ESP family, a multigene family with 38 genes in mice. ESP1 shares the highest homology with ESP4. ESP1 is expressed in the extraorbital lacrimal gland, whereas ESP4 is expressed in some exocrine glands. Thus, ESP4 is expected to have a function that has not been elucidated yet. Large amounts of the purified ESP4 protein are required for structural and biochemical studies. Here we present an expression and purification scheme for the recombinant ESP4 protein. The N-terminally histidine-tagged ESP4 fusion protein was expressed in Escherichia coli as inclusion bodies, which were solubilized and purified by nickel affinity chromatography. The histidine tag was cleaved with thrombin and removed by a second nickel affinity chromatography step. The ESP4 protein was isolated with high purity by reversed-phase chromatography. For NMR analyses, we prepared a stable isotope-labeled ESP4 protein. Three repeated freeze-drying steps after the reversed-phase chromatography were required, to remove a volatile contaminating compound and to obtain an NMR spectrum with a homogeneous line shape. AMS-modification and far-UV CD spectroscopic analyses suggested that ESP4 has an intramolecular disulfide bridge and a helical structure, respectively. The present study provides a powerful tool for structural and biochemical studies of ESP4, leading toward the elucidation of the roles of the ESP family members.
Department of Structural BioImaging, Faculty of Life Sciences, Kumamoto University, Chuo-ku, Kumamoto 862-0973, Japan.
Makoto
M
Hirakane
Department of Structural BioImaging, Faculty of Life Sciences, Kumamoto University, Chuo-ku, Kumamoto 862-0973, Japan.
Masahiro
M
Taniguchi
Department of Structural BioImaging, Faculty of Life Sciences, Kumamoto University, Chuo-ku, Kumamoto 862-0973, Japan.
Sosuke
S
Yoshinaga
Department of Environmental and Molecular Health Sciences, Faculty of Life Sciences, Kumamoto University, Chuo-ku, Kumamoto 862-0973, Japan.
Shogo
S
Misumi
Department of Structural BioImaging, Faculty of Life Sciences, Kumamoto University, Chuo-ku, Kumamoto 862-0973, Japan. Electronic address: terasawa@gpo.kumamoto-u.ac.jp.
Hiroaki
H
Terasawa
D000818:Animals; D002846:Chromatography, Affinity; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism*; D015870:Gene Expression; D002479:Inclusion Bodies / Q000378:metabolism; D051379:Mice; D019906:Nuclear Magnetic Resonance, Biomolecular; D010455:Peptides / Q000235:genetics* / Q000378:metabolism; D010675:Pheromones / Q000096:biosynthesis / Q000235:genetics*; D017433:Protein Structure, Secondary; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000235:genetics
D010455:Peptides; D010675:Pheromones; D011993:Recombinant Fusion Proteins; C000592918:exocrine gland-secreting peptide 4, mouse
Disulfide bridge; ESP; Escherichia coli expression; Histidine-tag purification; Inclusion bodies; pET system