Part:BBa_K519010

SmtA

SmtA is a metallothionein that can bind to heavy metal ions such as Cd(II). This SmtA is cloned from Synechococcus sp. PCC7942, a cyanobacterial strain. SmtA is a type II metallothionein with a reduced cys content.It was reported that marine cyanobacterium that does not originally harbor a homologous gene, when genetically engineered to express SmtA, could tolerate medium containing Cd(II), Zn(II) and Cu(II) (Sode et al., 1998).

The data above, taken from a paper (Sode et al., 1988), shows that a cyanobacterial strain was able to tolerate medium of high Cd(II) concentration when it harbored the smtA gene.

For our iGEM project this year, we have successfully observed that SmtA, expressed under a constitutive promoter (J23109) work very well. We plotted a graph of growth rate by looking at the OD595 every 1 hour, and compared the growth of wild type E. coli and SmtA expressing E. coli. As a result, we found that E. coli expressing SmtA grow better than the WT E. coli at a high Cd(II) concentration.

Sequence and Features

Assembly Compatibility:

• 10
  INCOMPATIBLE WITH RFC[10]

  Illegal PstI site found at 93
  
• 12
  INCOMPATIBLE WITH RFC[12]

  Illegal PstI site found at 93
  
• 21
  COMPATIBLE WITH RFC[21]
• 23
  INCOMPATIBLE WITH RFC[23]

  Illegal PstI site found at 93
  
• 25
  INCOMPATIBLE WITH RFC[25]

  Illegal PstI site found at 93
  Illegal AgeI site found at 121
  
• 1000
  COMPATIBLE WITH RFC[1000]

Functional Parameters

function	-NA-
n/a	SmtA

Functional Parameters: Austin_UTexas

Burden Imposed by this Part:

Burden Value: -0.1 ± 3.9%

Burden is the percent reduction in the growth rate of E. coli cells transformed with a plasmid containing this BioBrick (± values are 95% confidence limits). This BioBrick did not exhibit a burden that was significantly greater than zero (i.e., it appears to have little to no impact on growth). Therefore, users can depend on this part to remain stable for many bacterial cell divisions and in large culture volumes. Refer to any one of the BBa_K3174002 - BBa_K3174007 pages for more information on the methods, an explanation of the sources of burden, and other conclusions from a large-scale measurement project conducted by the 2019 Austin_UTexas team.

This functional parameter was added by the 2020 Austin_UTexas team.