Dear All,

As a person just being introduced the Pichia pastoris expression system, I have come across a couple of different documents stating the Pichia pastoris translation initiation site (Kozak) sequence differently:

(A/Y)A(A/T)AATGTCT (yeast, Romanos et al, 1992)

(G/A)NNATGG (Invitrogen manual, while, interestingly, their own alpha-factor starts with AAACGATGAGA...)

AAAACGATG (one of the synthetic gene companies)

Which one is right (most efficient)?

I read that TCT after ATG is about stability of N-term (N-end rule) but why is there a G right after ATG in Invitrogen manual?

Thanks,