Improvement of pre-existing Registry parts

Improved function by a modified Lac promoter - Mutations were introduced into the wild type Lac promoter that exists in the Registry. One mutant promoter, designated pLacIQ1, had improved ability to promote, as demonstrated by the following experiment.

Constructs were assembled with eiter the wild type Lac promoter or mutant promoters driving GFP expression via part number E0240. Fluorescence measurements taken at 16 or 24 hours were corrected for optical density.

16 hours

Sample	Fluorescence	Optical Density	Fluor/OD
LB	2	0.043	46.5
E0240	0.67	1.262	0.53
S04020	4.67	1.225	3.81
S04021	21	1.201	17.49
K091131	68	1.188	57.24

24 hours

Sample	Fluorescence	Optical Density	Fluor/OD
LB	1	0.047	21.3
E0240	3.0	1.201	2.50
S04020	4.0	1.239	3.23
S04021	14.5	1.216	11.92
K091131	71.3	1.207	59.07

Mutations were also introduced into the LacI repressor gene in order to improve its ability to bind to the operator site in the Lac promoter.

Part	Description	plasmid	size
BBa_K091121	LacI wild-type gene		1083
BBa_K091122	LacI_I12		1083
BBa_K091127	LacI_I12_X86		1083