Part:BBa_K177047

crobox alternative version

Derivative of OR3

Cro-box is the particular fragment of phage lambda DNA which is recognized by cro repressor protein. This sequence is artificially designed (based on natural fragment of lambda phage genome) to regulate the affinity of the cro protein.

Usage and Biology

When this part is introduced into a sequence of elements expressed from a single promoter the binding of the Cro protein (BBa_K177009) successfully inhibits the expression of elements located downstream.

Functional Parameters

This variant of the cro binding box differs from the OR1 (BBa_K177002) version by binding strength to Cro and λ repressor, as indicated by the free energy change, being -1.1 kcal/mol and 2.2 kcal/mol respectively.¹

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]

¹ Takeda Y., Sarai A., Rivera VM.; Analysis of the sequence-specific interactions between Cro repressor and operator DNA bt systematic base substitution experiments; Proc. Natl. Acad. Sci. USA, Vol. 86, pp. 439-443, January 1989