Part:BBa_I739105

Double Promoter (LuxR/HSL, positive / cI, negative)

Part Structure

The Biobrick consists of the whole non-constitutive promoter BBa_R0062 linked to twice the second operator sequence of BBa_R0051 (OR2).

The -35 and -10 regions, which are responsible for the binding of RNA-polymerase to DNA via sigma factors, are included in the BBa_R0062 promoter region (first part of the double promoter). No further functional -10 and -35 regions were included in the second part of the double promoter. Instead, two operator sequences of the same type were included in the second part. The reason for this is that the probability of a binding event (and hence regulation strength) is increased if a multiple of identical operator sequences is included in the regulatory sequence.

Summarized:
There are three operator sequences: 1xBBa_R0062 (LuxR/HSL), 2xBBa_R0051 (OR2).

Mode of Action

Regulation of the first part: Two molecules of LuxR protein form a complex with two molecules of the signalling compound homoserine lactone (HSL) (e.g. AHL). This complex binds to a palindromic site on the promoter BBa_R0062, increasing the rate of transcription.

Regulation of the second part: When lambda cI binds to the cI operator sequences, it represses transcription. There is no inducer which derepresses the promoter upon addition.

Purpose

This Biobrick was designed for the [http://2007.igem.org/ETHZ ETHZ iGEM 2007 project] and belongs to a first generation of double promoters. BBa_I739105 is part of biobrick BBa_I739007.

Testing

Checked for uniqueness of restriction enzyme cleavage sites:
Eco: ok
Xba: ok
Spe: ok
Pst: ok

Sequence and Features

Assembly Compatibility:

• 10
  COMPATIBLE WITH RFC[10]
• 12
  COMPATIBLE WITH RFC[12]
• 21
  COMPATIBLE WITH RFC[21]
• 23
  COMPATIBLE WITH RFC[23]
• 25
  COMPATIBLE WITH RFC[25]
• 1000
  COMPATIBLE WITH RFC[1000]