Purification and Characterization of Naturally Occurring Post-Translationally Cleaved Ara h 6 an Allergen That Contributes Substantially to the Allergenic Potency of Peanut

The 2S albumin Ara h 6 is one of the most important peanut allergens. A post-translationally cleaved Ara h 6 (pAra h 6) was purified from Virginia type peanuts, and the cleavage site was mapped using high-resolution mass spectrometry. Compared to intact Ara h 6, pAra h 6 lacks a 5-amino acid stretch, resembling amino acids 43-47 (UniProt...

Modulating state transition and mechanical properties of viscoelastic resins from maize zein through interactions with plasticizers and co-proteins

Viscoelastic properties have been observed in maize zein above its glass transition temperature; however, current understanding of how these viscoelastic polymers can be further manipulated for optimal performance is limited. Using resins formed via precipitation from aqueous ethanolic environments, this study presents a framework for...

Synthesis and evaluation of strand and turn modified ring-extended gramicidin S derivatives

In this paper, we describe the crystal structure of previously reported ring-extended gramicidin S (GS) derivative 2 (GS14K4), containing a d-amino acid residue in one of the β-strand regions. This structure is in agreement with a previously reported modeling study of the same molecule. The polar side chain of the additional d-amino acid residue...

Design approach of closed loop food systems in space

Interest on food production systems based on the cultivation of vegetables for future planetary exploration missions is increasing as these units can help overcoming difficult and costly re-supply logistics. In addition to producing edible biomass by growing vegetable species, these systems can be used in closed loop configuration with bio...

Quantitative description of the relation between protein net charge and protein adsorption to air-water interfaces

In this study a set of chemically engineered variants of ovalbumin was produced to study the effects of electrostatic charge on the adsorption kinetics and resulting surface pressure at the air-water interface. The modification itself was based on the coupling of succinic anhydride to lysine residues on the protein surface. After purification of...

Glycoforms of β-Lactoglobulin with Improved Thermostability and Preserved Structural Packing

In this article we show how various degrees of glycosylation can be used to control the thermal stability of proteins. The primary amines of β-lactoglobulin were glycosylated with glucose or fructose within a range of non-denaturing reaction parameters. The modified fractions were characterized and analyzed for structural stability and...

Transglutaminase-Mediated Modification of Glutamine and Lysine Residues in Native Bovine β-Lactoglobulin

Bovine β-lactoglobulin (BLG) is a major component in whey and its physical properties are important for the texture of many dairy-based foods. Modification of proteins with transglutaminase from Streptoverticillium mobaraense (MTGase) can be used to alter their physical properties. MTGase-mediated modification of native BLG was until now,...

Modification of β-lactoglobulin by oligofructose: Impact on protein adsorption at the air-water interface

Maillard products of β-lactoglobulin (βLg) and fructose oligosaccharide (FOS) were obtained in different degrees of modification depending on incubation time and pH. By use of a variety of biochemical and spectroscopic tools, it was demonstrated that the modification at limited degrees does not significantly affect the secondary, tertiary, and...

Tentative assignment of the potato serine protease inhibitor group as β-II proteins based on their spectroscopic characteristics

Potato serine protease inhibitor (PSPI) is the most abundant protease inhibitor group in potato tuber. The investigated PSPI isoforms have a highly similar structure at both the secondary and the tertiary level. From the results described, PSPI is classified as a β-II protein based on (1) the presence in the near-UV spectra of sharp peaks,...

Heat denaturation of soy glycinin: Influence of pH and ionic strength on molecular structure

The 7S/11S glycinin equilibrium as found in Lakemond et al. (J. Agric. Food Chem. 2000, 48, xxxxxxxx) at ambient temperatures influences heat denaturation. It is found that the 7S form of glycinin denatures at a lower temperature than the 11S form, as demonstrated by a combination of calorimetric (DSC) and circular dichroism (CD) experiments. At...

Localization of synthesis of β1,6-glucan in Saccharomyces cerevisiae

β1,6-Glucan is a key component of the yeast cell wall, interconnecting cell wall proteins, β1,3-glucan, and chitin. It has been postulated that the synthesis of β1,6-glucan begins in the endoplasmic reticulum with the formation of protein-bound primer structures and that these primer structures are extended in the Golgi complex by two putative...

Heat-induced conformational changes of Ara h 1, a major peanut allergen, do not affect its allergenic properties

Ara h 1, a major peanut allergen was isolated, and its structure on secondary, tertiary, and quaternary level at ambient temperature was investigated using spectroscopic and biochemical techniques. Ara h 1 appeared to be a highly structured protein on a secondary level, possesses a clear tertiary fold, and is present as a trimeric complex. Heat...

Heat-induced conformational changes of patatin, the major potato tuber protein

This paper presents a first structural characterization of isolated patatin, the major potato tuber protein, at ambient and elevated temperatures. Isolated patatin at room temperature is a highly structured molecule at both secondary and tertiary levels. It is estimated from far-ultraviolet circular dichroism data that about 33% of the residues...

Secondary structure of the intact H+,K+ -ATPase and of its membrane-embedded region. An attenuated total reflection infrared spectroscopy, circular dichroism and Raman spectroscopy study

Models of P-type ATPase predict that membrane-embedded fragments represent about 20% of the protein and adopt an all-α-helical structure. While this prediction was confirmed for the Ca2+ -ATPase [Corbalan-Garcia, S., Teruel, J., Villalain, J. and Gomez-Fernandez, J. (1994) Biochemistry 33, 8247-8254], it is at odds with recent experimental...

The Lactobacillus acidophilus S-layer protein gene expression site comprises two consensus promoter sequences, one of which directs transcription of stable mRNA

S-proteins are proteins which form a regular structure (S-layer) on the outside of the cell walls of many bacteria. Two S-protein-encoding genes are located in opposite directions on a 6.0-kb segment of the chromosome of Lactobacillus acidophilus ATCC 4356 bacteria. Inversion of this chromosomal segment occurs through recombination between two...

Molecular characterization of a saline-soluble lectin from a parasitic fungus: Extensive sequence similarities between fungal lectins

It has been proposed that the interactions between several parasite and pathogenic fungi and their hosts are mediated by soluble lectins present in the fungus. We have cloned and analyzed a gene encoding such a lectin (AOL) from the nematophagous fungus Arthrobotrys oligospora (deuteromycete). The deduced primary structure of the AOL gene...