Protein profiling of water and alkali soluble cottonseed protein isolates

Abstract

Currently, there is only limited knowledge on the protein types and structures of the cottonseed proteins. In this work, water-soluble cottonseed proteins (CSPw) and alkali-soluble cottonseed proteins (CSPa) were sequentially extracted from defatted cottonseed meal. Proteins of the two fractions were separated by 4–20% gradient polyacrylamide gel electrophoresis (SDS-PAGE); There were 7 and 12 polypeptide bands on SDS-PAGE of CSPa and CSPw, respectively. These individual bands were then excised from the gel and subjected to mass spectrometric analysis. There were total 70 polypeptides identified from the proteins of the two cottonseed preparations, with molecular weights ranging from 10 to 381 kDa. While many proteins or their fragments were found in multiple bands, 18 proteins appeared only in one SDS-PAGE band (6 in CSPa, 12 in CSPw). Putative functions of these proteins include storage, transcription/translation, synthesis, energy metabolism, antimicrobial activity, and embryogenesis. Among the most abundant are legumin A (58 kDa), legumin B (59 kDa), vicilin C72 (70 kDa), vicilin GC72-A (71 kDa), and vicilin-like antimicrobial peptides (62 kDa). This work enriched the fundamental knowledge on cottonseed protein composition, and would help in better understanding of the functional and physicochemical properties of cottonseed protein and for enhancing its biotechnological utilization.

In Silico, Molecular Docking and In Vitro Antimicrobial Activity of the Major Rapeseed Seed Storage Proteins

“…Sin a 1 has been shown to be related to B. rapa and B. napus napins at the sequence level ( Rahman et al, 2020 ). The database search also showed that rapeseed cruciferins ( Supplementary Table 1 ) have high similarity with rice glutelins which have been reported as antimicrobial peptides ( Bundó et al, 2014 ), as well as the antibacterial glycinin protein from G. max ( Sitohy et al, 2012 ; Yang et al, 2016 ) and antibacterial Legumin A (P09802) from Gossypium hirsutum L. ( Supplementary Figure 1B ) ( He et al, 2018 ). These results suggested the napin and cruciferin are most likely to have antimicrobial properties as well.…”

Comparative studies on seed protein characteristics in eight lines of two Gossypium species

“…Similarly, recent protein characterization studies on Gossypium species have reported 60~70% of the total seed proteins belonging to vicilin and legumin families; the later contributed more. These workers have also shown more heterogeneity in the molecular weights of the legumin A subunits (30 kDa, 17~20 kDa and 11~12 kDa) and less in legumin B subunits (11~13 kDa) (Hu et al 2011;He et al 2018). Further analysis indicated the polypeptide of molecular weight 58 kDa as a precursor of legumin A subunits.…”

“…vicilin and legumin accounting for 60~70% of cotton seed proteins (Hu et al 2011). A recent study on water-and alkali-soluble cottonseed proteins (He et al 2018) in G. hirsutum exhibited the presence of 6 and 12 major protein bands on SDS-PAGE belonging to CSPa and CSPw, respectively. Among these proteins, the most abundant peptides were shown to be legumin and vicilin types.…”

Sida hermaphrodita seeds as the source of anti - Candida albicans activity

“…There are also known derivatives of vicilins: a vicilin-like glycoprotein from Nicotiana sylvestris 46 and a low molecular weight vicilin-like glycoprotein from Citrullus lanatus seeds 47 . He and collaborators 48 revealed the presence of vicilin GC72-A in the cotton seed extract - a plant belonging to the Malvaceae family. The same protein was detected in the high molecular weight fraction analysed in our experiments.…”