A novel methanol assimilating yeast species Komagataella kurtzmanii is described using the type strain VKPM Y-727 (=KBP Y-2878 = UCD-FST 76-20 = Starmer #75-208.2 = CBS 12817 = NRRL Y-63667) isolated by W.T. Starmer from a fir flux in the Catalina Mountains, Southern AZ, USA. The new species is registered in MycoBank under MB 803919. The species was differentiated by divergence in gene sequences for D1/D2 LSU rRNA, ITS1-5.8S-ITS2, RNA polymerase subunit I, translation elongation factor-1α and mitochondrial small subunit rRNA. K. kurtzmanii differs from its phenotypically similar sibling species Komagataella pastoris, Komagataella pseudopastoris, Komagataella phaffii, Komagataella populi and Komagataella ulmi by absence of growth at 35 °C and inability to assimilate trehalose.
4081 The scheme of the metabolic pathways of methanol assimilation and dissimilation in methylotrophic yeasts of the genus Komagataella (Pichia) was described more than ten years ago and has not been substantially changed [1].The initial reaction of methanol oxidation is cata lyzed by the peroxisome alcohol oxidase Aox1p. This reaction results in the formation of formaldehyde and hydrogen peroxide. Part of the formaldehyde remains in peroxisomes and enters into the condensation reac tion with xylulose 5 phosphate, which is the first reaction of the assimilation pathway. The other part of formaldehyde passes into the cell cytoplasm to be fur ther oxidized via the dissimilation pathway. In the dis similation pathway, formaldehyde obtained as a result of methanol oxidation is translocated into the cyto plasm in the form of S hydroxymethyl glutathione, which is formed as a result of a noncatalytic reaction of reduced glutathione with formaldehyde. In the cytoplasm, S hydroxymethyl glutathione undergoes further oxidation by NAD dependent formaldehyde dehydrogenase. The resultant S formyl glutathione is hydrolyzed to formic acid and glutathione by S formyl glutathione hydrolase [2]. The last step of methanol dissimilation is NAD dependent oxidation of formate to carbon dioxide, which is catalyzed by formate dehy drogenase.Methanol induced AOX1, a powerful alcohol oxi dase promoter, is often used for heterologous expres 1 Corresponding author; e mail: dg_kozlov@genetika.ru sion [3]. The high efficiency of the expression systems developed depends on the strict regulation of the AOX1 promoter and its high activity under conditions of induction. The promoter is characterized by complete repression in K. phaffii cells growing on most carbon substrates, including glucose or glycerin, and by induction under growth on methanol [4]. Certain car bon substrates (sorbitol, alanine, trehalose, etc.) were shown to support the growth of K. phaffii cells without repressing the AOX1 when methanol was used as an inducer [5].At the same time, despite considerable progress [6, 7], a detailed mechanism of AOX1 induction is not completely understood. In particular, it remains unclear what compound is directly involved in induc tion of this promoter and in what way.In our previous work, not only methanol but also formic acid (the last metabolite in the methanol dis similation pathway) and its salts, formates, were shown to be efficient inducers of the AOX1 promoter. The measurements showed that, depending on the yeast species, the level of induction by formate may reach 70-90% of the level of induction by methanol [8].The fact that formic acid has an induction potential allowed us to suggest that a certain amount of metha nol acting as a direct AOX1 inducer is formed inside the cell from exogenous formic acid as a result of the action of the formaldehyde dehydrogenase and alco hol oxidase enzymes.Abstract-Apart from the toxic methanol, relatively safe formic acid and its salts (formates) were shown to act as efficient inducers of the AOX1 pr...
We have studied the efficiency of N-terminal processing of the antibody light chain depending on the structure of the leader sequence when expressed in the yeast Pichia pastoris. The humanized light kappa-chain of the murine antibody H3-1 and the Saccharomyces cerevisiae alpha-factor pre-pro-leader sequence (pre-pro-alpha-F) were used as models. The use of pre-region of the pre-pro-alpha-F alone or together with the Glu-Ala-linker leads to the slightly increased yield of the secreted L-chain but was accompanied by the incomplete N-terminal processing of the secreted product.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.