title: Escherichia coli maltose-binding protein is uncommonly effective at promoting the solubility of polypeptides to which it is fused.
abstract: Although it is usually possible to achieve a favorable yield of a recombinant protein in Escherichia coli, obtaining the protein in a soluble, biologically active form continues to be a major challenge. Sometimes this problem can be overcome by fusing an aggregation-prone polypeptide to a highly soluble partner. To study this phenomenon in greater detail, we compared the ability of three soluble fusion partners--maltose-binding protein (MBP), glutathione S-transferase (GST), and thioredoxin (TRX)--to inhibit the aggregation of six diverse proteins that normally accumulate in an insoluble form. Remarkably, we found that MBP is a far more effective solubilizing agent than the other two fusion partners. Moreover, we demonstrated that in some cases fusion to MBP can promote the proper folding of the attached protein into its biologically active conformation. Thus, MBP seems to be capable of functioning as a general molecular chaperone in the context of a fusion protein. A model is proposed to explain how MBP promotes the solubility and influences the folding of its fusion partners.
authors.affiliation: ABL-Basic Research Program, NCI-Frederick Cancer Research and Development Center, Maryland 21702-1201, USA.
authors.forename: R B
authors.initials: RB
authors.lastname: Kapust
authors.forename: D S
authors.initials: DS
authors.lastname: Waugh
mesh_terms: D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D001483:Base Sequence; D002352:Carrier Proteins / Q000737:chemistry* / Q000378:metabolism; D017931:DNA Primers; D004926:Escherichia coli / Q000737:chemistry*; D029968:Escherichia coli Proteins; D005982:Glutathione Transferase / Q000737:chemistry; D008320:Maltose / Q000378:metabolism; D058619:Maltose-Binding Proteins; D009004:Monosaccharide Transport Proteins; D017510:Protein Folding; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D012995:Solubility; D013879:Thioredoxins / Q000737:chemistry
chemical_list: D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; D002352:Carrier Proteins; D017931:DNA Primers; D029968:Escherichia coli Proteins; D058619:Maltose-Binding Proteins; D009004:Monosaccharide Transport Proteins; D011993:Recombinant Fusion Proteins; C461599:maltose transport system, E coli; D013879:Thioredoxins; D008320:Maltose; D005982:Glutathione Transferase