title: Mocr: a novel fusion tag for enhancing solubility that is compatible with structural biology applications.
abstract: A persistent problem in heterologous protein production is insolubility of the target protein when expressed to high level in the host cell. A widely employed strategy for overcoming this problem is the use of fusion tags. The best fusion tags promote solubility, may function as purification handles and either do not interfere with downstream applications or may be removed from the passenger protein preparation. A novel fusion tag is identified that meets these criteria. This fusion tag is a monomeric mutant of the Ocr protein (0.3 gene product) of bacteriophage T7. This fusion tag displays solubilizing activity with a variety of different passenger proteins. We show that it may be used as a purification handle similar to other fusion tags. Its small size and compact structure are compatible with its use in downstream applications of the passenger protein or it may be removed and purified away from the passenger protein. The use of monomeric Ocr (Mocr) as a complement to other fusion tags such as maltose-binding protein will provide greater flexibility in protein production and processing for a wide variety of protein applications.
authors.affiliation: High-throughput Protein Lab, Center for Structural Biology, Life Sciences Institute, University of Michigan, 210 Washtenaw Avenue, Ann Arbor, Michigan 48109, USA.
authors.forename: James
authors.initials: J
authors.lastname: DelProposto
authors.forename: Chinmay Y
authors.initials: CY
authors.lastname: Majmudar
authors.forename: Janet L
authors.initials: JL
authors.lastname: Smith
authors.forename: William Clay
authors.initials: WC
authors.lastname: Brown
mesh_terms: D019943:Amino Acid Substitution; D002853:Chromatography, Liquid; D003001:Cloning, Molecular; D004983:Ethanolamines; D016133:Polymerase Chain Reaction; D040081:Protein Array Analysis; D020836:Protein Structure, Quaternary; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D020539:Sequence Analysis, Protein; D012995:Solubility; D014764:Viral Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D004983:Ethanolamines; C440255:Ocr protein, bacteriophage T7; D011993:Recombinant Fusion Proteins; D014764:Viral Proteins; C007369:2-diethylaminoethanol