Abstract: The invention provides composition and methods for producing proteins of interest which comprise at least one disulfide bond, include proteins which in their mature form do not contain disulfide bonds, but whose precursor molecule contained at least one disulfide bond. The methods employ a host cell modified to more efficiently produce properly folded disulfide bond containing proteins. The host cells generally contain a mutation in one or more reductase genes, and can be further genetically modified to increase their growth rate, and are further optionally modified to increase the expression of a catalyst of disulfide bond formation. Host cells, methods for using such to produce proteins of interest, proteins of interest produced by these methods are within the scope of the invention.

Abstract: The invention provides composition and methods for producing proteins of interest which comprise at least one disulfide bond, include proteins which in their mature form do not contain disulfide bonds, but whose precursor molecule contained at least one disulfide bond. The methods employ a host cell modified to more efficiently produce properly folded disulfide bond containing proteins. The host cells generally contain a mutation in one or more reductase genes, and can be further genetically modified to increase their growth rate, and are further optionally modified to increase the expression of a catalyst of disulfide bond formation. Host cells, methods for using such to produce proteins of interest, proteins of interest produced by these methods are within the scope of the invention.

Abstract: An export sequence of export DNA can be identified by transforming a population of cells with a vector having a transposon that includes a structural gene encoding a detectable compound, positioned between insertion sequences. The structural gene encodes a detectable compound that, in wild-type organisms, is translated with an export peptide effective to export the compound. Since the transposon lacks DNA coding for an export sequence capable of exporting the detectable gene product, transformants that export the gene product include a DNA fusion of the transposon to export DNA from the parent cell, in a position to allow expression of the fused DNA. The transformants are analyzed to locate the export DNA or a gene comprising it, and the position of the export DNA in the cell's genome is determined; the orientation of the insertion also is determined.