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Insight into factors directing high production of eukaryotic membrane proteins; production of 13 human AQPs in Pichia pastoris.

Fredrik Öberg ; Mikael Ekvall ; Maria Nyblom (Institutionen för kemi- och bioteknik, Molekylär mikroskopi) ; Anna Backmark (Institutionen för kemi- och bioteknik) ; Richard Neutze ; Kristina Hedfalk
Molecular membrane biology (1464-5203). Vol. 26 (2009), 4, p. 215-27.
[Artikel, refereegranskad vetenskaplig]

Membrane proteins are key players in all living cells. To achieve a better understanding of membrane protein function, significant amounts of purified protein are required for functional and structural analyses. Overproduction of eukaryotic membrane proteins, in particular, is thus an essential yet non-trivial task. Hence, improved understanding of factors which direct a high production of eukaryotic membrane proteins is desirable. In this study we have compared the overproduction of all human aquaporins in the eukaryotic host Pichia pastoris. We report quantitated production levels of each homologue and the extent of their membrane localization. Our results show that the protein production levels vary substantially, even between highly homologous aquaporins. A correlation between the extents of membrane insertion with protein function also emerged, with a higher extent of membrane insertion for pure water transporters compared to aquaporin family members with other substrate specificity. Nevertheless, the nucleic acid sequence of the second codon appears to play an important role in overproduction. Constructs containing guanine at the first position of this codon (being part of the mammalian Kozak sequence) are generally produced at a higher level, which is confirmed for hAQP8. In addition, mimicking the yeast consensus sequence (ATGTCT) apparently has a negative influence on the production level, as shown for hAQP1. Moreover, by mutational analysis we show that the yield of hAQP4 can be heavily improved by directing the protein folding pathway as well as stabilizing the aquaporin tetramer.

Nyckelord: Aquaporins, chemistry, classification, genetics, metabolism, Codon, genetics, Humans, Immunoblotting, Models, Biological, Phylogeny, Pichia, genetics, metabolism

Denna post skapades 2009-10-21. Senast ändrad 2011-01-20.
CPL Pubid: 100488


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Institutioner (Chalmers)

Institutionen för kemi (2001-2011)
Institutionen för kemi- och bioteknik, Molekylär mikroskopi (2008-2014)
Institutionen för kemi- och bioteknik (2005-2014)



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