Abstract: It is an object to provide a protein having a dockerin, which is suited to production in yeasts and other eukaryotic microorganism in which sugar chain modification is predicted, and which provides excellent cohesin-dockerin binding ability, along with a use thereof. The present invention uses, as a protein for constructing a protein complex using a scaffolding protein having a type I cohesin from Clostridium thermocellum, a protein having a dockerin having at least one dockerin-specific sequence which is a dockerin-specific sequence associated with cohesin binding in type I dockerins from C. thermocellum, and which either has no intrinsic predicted N-type sugar chain modification site or has aspartic acid substituted for the asparagine of an intrinsic predicted N-type sugar chain modification site.

Abstract: The present invention provides an artificial scaffolding material for retaining proteins suitable for placing contiguously one species or two or more species of proteins such as enzymes. To this end, the artificial scaffolding material for retaining proteins is provided with a cell and scaffolding proteins heterologous to the cell and placed on the surface layer side of the cell at an extent that allows aggregation properties to be conferred to the cell, and provided with a plurality of non-covalently binding protein-binding domains arranged in tandem.

Abstract: The present invention provides a transformant into which has been incorporated DNA for coding a foreign protein having lactate dehydrogenase activity and provided with pyruvic acid substrate affinity that equals or exceeds the pyruvic acid substrate affinity of the pyruvate decarboxylase inherent in the host organism. Said transformant can stably mass-produce lactic acid inside a host organism having the pyruvate decarboxylase gene.

Abstract: It is an object to provide a protein having a dockerin, which is suited to production in yeasts and other eukaryotic microorganism in which sugar chain modification is predicted, and which provides excellent cohesin-dockerin binding ability, along with a use thereof. The present invention uses, as a protein for constructing a protein complex using a scaffolding protein having a type I cohesin from Clostridium thermocellum, a protein having a dockerin having at least one dockerin-specific sequence which is a dockerin-specific sequence associated with cohesin binding in type I dockerins from C. thermocellum, and which either has no intrinsic predicted N-type sugar chain modification site or has aspartic acid substituted for the asparagine of an intrinsic predicted N-type sugar chain modification site.

Abstract: The present invention provides an artificial scaffolding material for retaining proteins suitable for placing contiguously one species or two or more species of proteins such as enzymes. To this end, the artificial scaffolding material for retaining proteins is provided with a cell and scaffolding proteins heterologous to the cell and placed on the surface layer side of the cell at an extent that allows aggregation properties to be conferred to the cell, and provided with a plurality of non-covalently binding protein-binding domains arranged in tandem.

Abstract: The present invention provides a transformant into which has been incorporated DNA for coding a foreign protein having lactate dehydrogenase activity and provided with pyruvic acid substrate affinity that equals or exceeds the pyruvic acid substrate affinity of the pyruvate decarboxylase inherent in the host organism. Said transformant can stably mass-produce lactic acid inside a host organism having the pyruvate decarboxylase gene.

Abstract: A basic antimicrobial protein is activated by a partner protein having an isoelectric point below pH 7 and a chaperon function, by expressing an antimicrobially inactive fusion protein between the basic antimicrobial protein and the partner protein, recovering the fusion protein and separating the two proteins from each other. In such manner, an advantageous mass expression system of the basic antimicrobial protein having an appropriate disulfide bond as an active type is realized at lost cost.

Abstract: A method for detecting or quantitating a mutagenic substance in a sample includes culturing a host microorganism transformed with a recombinant gene comprising an SOS gene and genes expressing luciferase activity and optionally genes expressing an enzyme which catalyzes the production of a substrate for luciferase, positioned downstream of the SOS gene, in a medium to which the sample is added; and measuring a luminescence generated by expression of the gene expressing luciferase activity. The method is sensitive, accurate and non-time consuming; and gene systems used for said method, i.e., a recombinant gene comprising an SOS gene expressed when a DNA is damaged and a gene expressing luciferase activity positioned downstream of the SOS gene, and a host microorganism transformed with said recombinant gene. Preferably the recombinant gene further comprises a gene expressing an enzyme which catalyses the production of a substrate for the luciferase in the down stream of the SOS gene.

Abstract: A highly thermostable polypeptide possessing protein disulfide isomerase (PDI) activity, a gene coding for the polypeptide and a process for producing the polyeptide are provided. The polypeptide possessing PDI activity is characterized by A) having a capability of catalyzing a disulfide exchange in proteins, B) recognizing mainly ribonuclease A as a substrate, C) having a suitable active temperature of 20.degree. to 70.degree. C., D) being stable at a pH value of 6 to 9, and E) having a molecular weight of about 60,000 to 62,000. Since it has a higher thermostability and exhibits a stable activity in a wider dithiothreitol concentration range as compared with the conventional PDI, it is possible to provide a novel enzyme active protein which can be advantageously used for a refolding reaction of certain proteins.

Abstract: A highly thermostable polypeptide possessing protein disulfide isomerase (PDI) activity, a gene coding for the polypeptide and a process for producing the polypeptide are provided. The polypeptide possessing PDI activity is characterized by A) having a capability of catalyzing a disulfide exchange in proteins, B) recognizing mainly ribonuclease A as a substrate, C) having a suitable active temperature of 20.degree. to 70.degree. C., D) being stable at a pH value of 6 to 9, and E) having a molecular weight of about 60,000 to 62,000. Since it has a higher thermostability and exhibits a stable activity in a wider dithiothreitol concentration range as compared with the conventional PDI, it is possible to provide a novel enzyme active protein which can be advantageously used for a refolding reaction of certain proteins.