TABLE 3.

List of plasmids used in this study

Name	Description	Source or reference
pPRO-folA	E. coli folA gene cloned into pPRO-Ex-Htb plasmid for heterologous expression (adds a hexa-His tag at the N terminus)	31
pPRO-folA P21L/P21Q/P21T/P21R/P21S	Derivative of pPRO-folA expressing Pro21 mutants of DHFR	31, this study
pPRO-folA W30R/W30G/W30L/W30S/W30C	Derivative of pPRO-folA expressing Trp30 mutants of DHFR	31, this study
pPRO-folA I94V/I94F/I94L/I94S/I94N/I94T/I94M	Derivative of pPRO-folA expressing Ile94 mutants of DHFR	31, this study
pBAD33-Lon	Plasmid for expression of Lon protease from an arabinose inducible promoter	38
pKD46	Plasmid for expression of lambda red recombination proteins	55
pKD4	Plasmid used as the template for amplification of kanamycin resistance cassette	55
pKD3	Plasmid used as the template for amplification of chloramphenicol resistance cassette	55