Part:BBa_K1668003

orfX (from Streptomyces avermitilis, increasing avermectin production) aaaaaaaaaaaaaaaaaa metK is the S-adenosylmethionine synthetase gene from Streptomyces avermitilis, which was found to stimulate the production of avermectins. When wild-type strain ATCC31267 was transformed with pYJ02 and pYJ03, two metK expression plasmids, avermectin production was increased about 2.0-fold and 5.5-fold compared with that in the control strains, respectively. The avermectin productivity of each culture was quantitatively measured by HPLC analysis.

As the kinetic study revealed, avermectin overproduction in recombinant strain was not caused by the change of cell growth rate or copy number effect. Instead, metK stimulates the avermectin production by increasing the intracellular concentration of S-adenosylmethionine (SAM), an important intermediate product in avermectin production. However, there may be a maximum concentration of SAM for the production of avermectin in S. avermitilis, over which it has no any effect on the antibiotic production.

The results of experiments showed that there were different effects of metK expression levels on avermectin production in various S. avermitilis strains. The gene expression levels of metK in two engineered strain, GB-165 and 76-05, were much higher then those in wild-type strain, whereas the avermectin productivity in these two strains were not significantly improved. It probably because the high expression level of metK limited the increasement of avermectin by overexpression of metK.

Sequence and Features

Assembly Compatibility:

• 10
  COMPATIBLE WITH RFC[10]
• 12
  INCOMPATIBLE WITH RFC[12]

  Illegal NotI site found at 160
  Illegal NotI site found at 247
  Illegal NotI site found at 361
  Illegal NotI site found at 595
  Illegal NotI site found at 745
  
• 21
  INCOMPATIBLE WITH RFC[21]

  Illegal XhoI site found at 510
  
• 23
  COMPATIBLE WITH RFC[23]
• 25
  INCOMPATIBLE WITH RFC[25]

  Illegal NgoMIV site found at 463
  Illegal AgeI site found at 264
  
• 1000
  INCOMPATIBLE WITH RFC[1000]

  Illegal BsaI site found at 441
  Illegal BsaI.rc site found at 195