Oleosin Isoforms of High and Low Molecular Weights Are Present in the Oil Bodies of Diverse Seed Species

Abstract

Oleosins are unique and major proteins localized on the surface of oil bodies in diverse seed species. We purified five different KD 20), and raised chicken antibodies against them. These antibodies were used to test for immunological cross-reactivity among oleosins from diverse seed species. Within the same seed species, antibodies raised against one oleosin isoform did not cross-react with the other oleosin isoform (i.e. between maize oleosins KD 16 and KD 18, and between soybean oleosins KD 18 and KD 24). However, the respective antibodies were able to recognize oleosins from other seed species. Where interspecies cross-reactivity occurred, the results suggest that there are at least two immunologically distinct isoforms of oleosins present in diverse seed species, one of lower Mr, and another one of higher Mr. This suggestion is also supported by the relative similarities between the amino acid sequence of a small portion of rapeseed oleosin KD 20 and those of maize oleosins KD 16 and KD 18. In maize kemel, there was a tissue-specific differential presentation of the three oleosins, KD 16, KD 18, and KD 19, in the oil-storing scutellum, embryonic axis, and aleurone layer. The phylogenetic relationship between the high and low Mr isoforms within the same, and among diverse, seed species is discussed.

Stable Mixed Beverage is Produced from Walnut Milk and Raw Soymilk by Homogenization with Subsequent Heating

“…Generally, the MWs of plant seed oil body oleosins are in a range of 16 _ 24 kDa (Tzen et al, 1990). Therefore, it was considered that the bands indicated by three arrows (Fig.…”

Specialization of Oleosins in Oil Body Dynamics during Seed Development in Arabidopsis Seeds

“…In Arabidopsis, 10 proteins have been identified, and seed-specific oleosins represent up to 79% of the OB proteins (Jolivet et al, 2004;D'Andréa et al, 2007;Vermachova et al, 2011). Oleosins are rather small proteins of 18.5 to 21.2 kD with a specific and highly conserved central hydrophobic domain of 72 amino acid residues flanked by hydrophilic domains of variable size and amino acid composition (Qu and Huang, 1990;Tzen et al, 1990Huang, 1996;Hsieh and Huang, 2004). It is generally agreed that oleosins cover the OB surface, with their central hydrophobic domain inserted in the TAG through the phospholipid layer .…”

Oleosin fusion expression systems for the production of recombinant proteins

“…For example, three maize oleosins (16, 18, 19 kDa) together represent about 5-6% of the total embryonic proteins; three soybean oleosins (18, 24, 34 kDa) account for about 3-4% of the total embryonic proteins; the major rapeseed oleosin (20 kDa) alone amounts to about 7-8% of the total embryonic proteins (Tzen et al 1990). One of the abovementioned oleosins can potentially be selected as the carriers for producing the desired protein.…”

“…Additionally, several oleosin isomers form a family in one species, with distinct expression characters. For example, the 24 kDa oleosin accounts for only 10% of the 20 kDa oleosin in rapeseed (Tzen et al 1990). …”

“…Each oleosin protein consists of three domains ( Fig. 1): (i) a highly conserved hydrophobic central anti-parallel β-stranded domain; (ii) an amphipathic N-terminal stretch; and (iii) an amphipathic α-helical C-terminal stretch, for localizing oleosin stably onto the surface of an oil body (Tzen et al 1990). The varieties of the N-terminal stretch and an additional extension at the C-terminus result in different sizes of oleosins (Huang 1996).…”