Patent ID: 8318481

Claim:
A plasmid having an improved copy number compared to a control plasmid, wherein said improved copy number plasmid has a mutation in a replication control region of said improved copy number plasmid relative to the replication control region of said control plasmid, and wherein said control plasmid comprises the replication control region sequence set forth in SEQ ID NO: 1 or a nucleotide sequence encoding the amino acid sequence set forth in SEQ ID NO:2, wherein the mutation in said improved copy number plasmid results in a change in the amino acid corresponding to: a. residue 91 of SEQ ID NO:2, wherein residue 91 is changed to a glycine or a conservative substitution of glycine, and wherein the copy number of the improved copy number plasmid is about 15-fold to about 35-fold higher than that of the control plasmid, or; b. residue 93 of SEQ ID NO:2, wherein residue 93 is changed to a leucine or a conservative substitution of leucine, and wherein the copy number of the improved copy number plasmid is about 15-fold to about 83-fold higher than that of the control plasmid.