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Kluyveromyces marxianus alpha mating-factor secretion signal

K.marxianus mα is a α-mating secretion signal in Kluyveromyces marxianus that encodes for a α-mating factor (αMF) domain fusing with desired protein. The signal peptide in αMF domain expressed direct the fusion protein into endoplasmic reticulum (ER), Golgi body and thus secrete in vitro. K.marxianus αMF is integrated upstream of gene of interest (e.g NpaBGS-t) to express a αMF domain fused with desired protein (enzymes e.g NpaBGS-t), which direct the enzyme to secrete from the host cell. The design eliminates process of lysing host cell and purifying desired proteins therefore reduce the cost of the whole textile degradation process. The integrated part αMF also provides a inspiration of extracellular protein secretion for future iGEM teams, paving the way of improving the efficiency of their protein secretion system.

Usage and Biology

The alpha-mating factor secretion signal consists of two regions: pre- and pro-secretion leader. The pre-secretion leader guides the protein of interest to the Sec61 translocon on the surface of endoplasmic reticulum via its binding with signal-regconition particles (SRPs). The pre-secretion leader is cleaved by the signal peptidase following the translocation of the protein into ER. The pro-secretion leader is further processed by Kex2 endopeptidase in the golgi apparatus at the site KR-EASA. The processed EASA residues are rapidly cleaved off by the Ste13 dipeptidase.

Design Considerations

1. The sequence of K.marxianus alpha-mating factor secretion signal is derived from the genomic sequence of K.marxianus strain DMKU3-1042.

2. The Kex2 cleavage site (KR-EA) is highly-conserved between S.serevisae and K.marxianus, but S.serevisiae and P.pastoris shares an EAEA sequence, whilst K.marxianus has an EASA sequence. Other variations in the signal sequence is also emergent. Sequence and Features

Sequence And Features