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. Author manuscript; available in PMC: 2013 Dec 5.
Published in final edited form as: J Am Chem Soc. 2012 Nov 20;134(48):19731–19738. doi: 10.1021/ja308049u

Table 1.

New E. coli amino acid auxotroph host strains used for overexpression of foreign genes

Strain Precursor strain Genes deleted Selective amino acid labeling References
ML40K1a C43(DE3) ilvE avtA aspC hisG argH metA lysA Ile, Val, His, Arg, Met, Lys, Leu,b Tyrc Ref. [40]
YM154a,d C43(DE3) cysE Cys Unpublishedd
RF3 BL21(DE3) aspC N.A.e This work
RF4RILa BL21(DE3) aspC, tyrB Tyr, Phe This work
a

These strains can be used for overexpression of foreign genes with rare codons (Fig. 2, step 5).

b

In the presence of 0.4–1 mM Tyr, tyrB is repressed and Leu is required for growth in minimal medium.40 This strategy can only be applicable for a short-term cultivation but not suitable for a long-term cultivation for heterologous expression of foreign genes.

c

In the presence of 0.4–1 mM Tyr, tyrB is repressed and Tyr is required for growth in minimal medium.40 This strategy can only be applicable for a short-term cultivation but not suitable for a long-term cultivation for heterologous expression of foreign genes.

d

C43(DE3) strain YM154 is a new cysteine auxotroph that grows normally in Luria-Bertani medium, but poorly in nonlabeled CHL medium with negligible amount of L-cysteine [to be published].

e

Not applicable. BL21(DE3) strain RF3 is a precursor without any resistance cassette (Fig. 2, step 4) and was used for construction of the RF4RIL strain.