Part:BBa_K4229003

TnaB tryptophan transport protein

The low affinity tryptophan permease TnaB is involved in the transport of tryptophan across the cytoplasmic membrane. It is a multi-pass membrane protein.

As one part of our toolbox to produce indigo/indirubin, we express TnaB to improve the cellular uptake of L-tryptophan.

Figure 1: Schematic representation of the indigo/indirubin pathway. L-Tryptophan is imported by the membrane protein TnaB (low affinity tryptophan permease). L-tryptophan is cleaved into indole, NH4+ and pyruvate by the Tryptophanase TnaA. The reaction continues by the hydroxylation of indole through XiaI. To enhance the effectivity of this enzyme, the NAD(P)H-flavin reductase provides XiaI with FADH2 by adding Hydrogen to FAD. Finally, indole is transformed to either 3-Hydroxyindole or 2-Hydroxyindole. These two substances spontaneously react to 3-Oxindole and 2-Oxindole through the secession of hydrogen from the OH-group. Through spontaneous dimerization indigo and indirubin are formed. Graphic adapted from [1].

References:
[1] H. Yin et al., “Efficient Bioproduction of Indigo and Indirubin by Optimizing a Novel Terpenoid Cyclase XiaI in Escherichia coli,” ACS Omega, vol. 6, no. 31, pp. 20569–20576, 2021, doi: 10.1021/acsomega.1c02679.

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]