Influence of acylation on the adsorption of GLP-2 to hydrophobic surfaces
Pinholt, C. ; Kapp, S.J. ; Bukrinsky, J.T. ; Hostrup, S. ; Frokjer, S. ; Norde, W. ; Jorgensen, L. - \ 2013
International Journal of Pharmaceutics 440 (2013). - ISSN 0378-5173 - p. 63 - 71.
glucagon-like peptide-2 - protein adsorption - reversible lipidization - albumin-binding - solid-surfaces - human insulin - fatty-acids - in-vivo - analog - desmopressin
Acylation of proteins with a fatty acid chain has proven useful for prolonging the plasma half-lives of proteins. In formulation of acylated protein drugs, knowledge about the effect of acylation with fatty acids on the adsorption behaviour of proteins at interfaces will be valuable. The aim of this work was to study the effect of acylation on the adsorption of GLP-2 from aqueous solution to a hydrophobic surface by comparing the adsorption of the 3766 Da GLP-2 with that of a GLP-2 variant acylated with a 16-carbon fatty acid chain through a ß-alanine linker. Adsorption of GLP-2 and acylated GLP-2 were studied with isothermal titration calorimetry, fixed-angle optical reflectometry and total internal reflection fluorescence. Furthermore, the effect of acylation of GLP-2 on the secondary structure was studied with Far-UV CD. Acylation was observed to have several effects on the adsorption of GLP-2. Acylation increased the amount of GLP-2 adsorbing per unit surface area and decreased the initial adsorption rate of GLP-2. Finally, acylation increased the strength of the adsorption, as judged by the lower fraction desorbing upon rinsing with buffer.
Nonmendelian inheritance of the HET-s prion or HET-s prion domains determines the het-S spore killing system in Podospora anserina
Dalstra, H.J.P. ; Zee, R.I. van der; Swart, K. ; Hoekstra, R.F. ; Saupe, S.J. ; Debets, A.J.M. - \ 2005
Fungal Genetics and Biology 42 (2005)10. - ISSN 1087-1845 - p. 836 - 847.
meiotic drive - heterokaryon incompatibility - vegetative incompatibility - in-vivo - protein - neurospora - fungi - organization - analog - genes
Two alleles of the het-s/S locus occur naturally in the filamentous fungus Podospora anserina, het-s and het-S. The het-s encoded protein can form a prion that propagates a self-perpetuating amyloid aggregate, resulting in two phenotypes for the het-s strains. The prion-infected [Het-s] shows an antagonistic interaction to het-S whereas the prion-free [Het-s*] is neutral in interaction to het-S. The antagonism between [Het-s] and het-S is seen as heterokaryon incompatibility at the somatic level and as het-S spore killing in the sexual cycle. Two different domains of the HET-s and HET-S proteins have been identified, and a structure-function relationship has been established for interactions at the somatic level. In this study, we correlate accumulation of the HET-s and HET-S proteins (visualized using GFP) during the sexual cycle with timing of het-S spore abortion. Also, we present the structure-function relationship of the HET-s domains for interactions in the sexual cycle. We show that the constructs that ensure het-s incompatibility function in somatic mycelium are also active in het-S spore killing in the sexual cycle. In addition, paternal prion transmission and het-S spore killing has been found with the HET-s(157-289) truncated protein. The consequences of the unique transition from a coenocytic to a cellular state in the sexual phase and the timing, and localization of paternal and maternal HET-s and HET-S expression that are pertinent to prion transmission, and het-S spore killing are elaborated. These data further support our previously proposed model for het-S spore killing.
Sexual transmission of the [Het-s] prion leads to meiotic drive in Podospora anserina
Dalstra, H.J.P. ; Swart, K. ; Debets, A.J.M. ; Saupe, S.J. ; Hoekstra, R.F. - \ 2003
Proceedings of the National Academy of Sciences of the United States of America 100 (2003). - ISSN 0027-8424 - p. 6616 - 6621.
fungus podospora-anserina - heterokaryon incompatibility - spore killer - filamentous fungi - neurospora - protein - elements - products - meiosis - analog
In the filamentous fungus Podospora anserina, two phenomena are associated with polymorphism at the het-s locus, vegetative incompatibility and ascospore abortion. Two het-s alleles occur naturally, het-s and het-S. The het-s encoded protein is a prion propagating as a self-perpetuating amyloid aggregate. When prion-infected [Het-s] hyphae fuse with [Het-S] hyphae, the resulting heterokaryotic cells necrotize. [Het-s] and [Het-S] strains are sexually compatible. When, however, a female [Het-s] crosses with [Het-S], a significant percentage of het-S spores abort, in a way similar to spore killing in Neurospora and Podospora. We report here that sexual transmission of the [Het-s] prion after nonisogamous mating in the reproductive cycle of Podospora is responsible for the killing of het-S spores. Progeny of crosses between isogenic strains with distinct wild-type or introduced, ectopic het-s/S alleles were cytologically and genetically analyzed. The effect of het-s/S overexpression, ectopic het-s/S expression, absence of het-s expression, loss of [Het-s] prion infection, and the distribution patterns of HET-s/S-GFP proteins were categorized during meiosis and ascospore formation. This study unveiled a het-S spore-killing system that is governed by dosage of and interaction between the [Het-s] prion and the HET-S protein. Due to this property of the [Het-s] prion, the het-s allele acts as a meiotic drive element favoring maintenance of the prion-forming allele in natural populations.