Abstract: Method and kit for constructing a random mutagenesis library. The method comprises providing a first expression vector comprising a target polynucleotide fragment, providing a pair of Vector-primers that are complementary to the vector portion of the first expression vector, wherein the Vector-primers comprise a second selection marker gene, and wherein the Vector-primers allow PCR amplification of the target polynucleotide; and performing a PCR reaction using the first expression vector as the template with the Vector-primers under error-prone PCR conditions in the presence of a thermostable DNA ligase, generating a second expression vector which comprises the second selection marker gene and a mutated target polynucleotide.

Abstract: Method and kit for constructing a random mutagenesis library. The method comprises providing a first expression vector comprising a target polynucleotide fragment, providing a pair of Vector-primers that are complementary to the vector portion of the first expression vector, wherein the Vector-primers comprise a second selection marker gene, and wherein the Vector-primers allow PCR amplification of the target polynucleotide; and performing a PCR reaction using the first expression vector as the template with the Vector-primers under error-prone PCR conditions in the presence of a thermostable DNA ligase, generating a second expression vector which comprises the second selection marker gene and a mutated target polynucleotide.

Abstract: This invention discloses an expression vector system comprising a promoter recognized and regulated by a heat shock sigma factor of E. coli, especially ?32. Preferably, the promoter comprises the consensus sequence of E. coli heat shock promoters as shown in SEQ ID NO:1. Also disclosed are methods for producing proteins using the promoter under heat shock conditions. Furthermore, the present invention discloses a method for creating a sudden temperature shift in a cell culture which has been pre-cultured to reach an optimal condition and which temperature shift will allow optimal production of a recombinant protein under the control a heat shock promoter.

Abstract: This invention discloses an expression vector system comprising a promoter recognized and regulated by a heat shock sigma factor of E. coli, especially ?32 . Preferably, the promoter comprises the consensus sequence of E. coli heat shock promoters as shown in SEQ ID NO:1. Also disclosed are methods for producing proteins using the promoter under heat shock conditions. Furthermore, the present invention discloses a method for creating a sudden temperature shift in a cell culture which has been pre-cultured to reach an optimal condition and which temperature shift will allow optimal production of a recombinant protein under the control a heat shock promoter.