The Gateway cloning system utilizes what Life Technologies refers to as "Clonase enzyme mix" to catalyze the BP and LR reactions.

What is in this enzyme mix? Is there a sequence for them?

  • $\begingroup$ I would imagine that if they're not listed on the datasheet, you're not going to be able to find out what they are... $\endgroup$
    – MattDMo
    May 2 '14 at 19:16
  • $\begingroup$ @MattDMo The manual (publication number MAN0000282) does mention that they are "Int, Xis, IHF". Are these actual genes? I would expect they are engineered further, but do the native genes not work at all? $\endgroup$
    – Superbest
    May 2 '14 at 19:48
  • 2
    $\begingroup$ @Superbest they are recombinases. Usually the enzymes that are used in the lab are engineered to some extent, for better stability and efficacy. $\endgroup$
    May 3 '14 at 4:10

The prototypes for these proteins are:

the bacteriophage λ proteins Int and Xis, required for, respectively the integration and excision of prophages. They are, as mentioned by @WYSIWYG, recombinases.

enter image description here

Genetic map of bacteriophage λ (source of image)

the original Ihf (integrative/integration host factor) was identified as an E. coli protein required for prophage integration.

As you might expect Int and Xis proteins occur in many phage genomes, and in integrated prophages in bacterial genomes, and Ihf, because it is involved in bacterial DNA replication, is ubiquitous. I imagine the actual source of the proteins used by Life Technologies could be a trade secret.


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