Novel high-yield potato protease inhibitor panels block a wide array of proteases involved in viral infection and crucial tissue damage.

Viruses critically rely on various proteases to ensure host cell entry and replication. In response to viral infection, the host will induce acute tissue inflammation pulled by granulocytes. Upon hyperactivation, neutrophil granulocytes may cause undue tissue damage through proteolytic degradation of the extracellular matrix.

Potato Patatin Generates Short-Chain Fatty Acids from Milk Fat that Contribute to Flavour Development in Cheese Ripening.

The potato lipase, patatin, has long been thought of as essentially inactive towards triacylglycerols. Recently, technology has been developed to isolate potato proteins in native form as food ingredients at industrial scale. Characterisation of native patatin obtained in this way revealed that this enzyme activity towards triacylglycerols has been underestimated.

Large-scale single step partial purification of potato pectin methylesterase that enables the use in major food applications.

Pectin methylesterase was extracted from potato tubers and partially purified in a single chromatographic step at large industrial scale. The preparation obtained in this way matched the temperature and pH profile of the species reported earlier by Puri et al. (Food Chemistry 8:203-213, 1982) and was enriched 23 times relative to the original potato tubers on a dry matter basis.

Digestion kinetics of potato protein isolates in vitro and in vivo.

Recently, an industrial process was developed to isolate native protein fractions from potato: a high (HMW) and a low (LMW) molecular weight fraction. Digestion kinetics of HMW and LMW was studied in vitro and in vivo and compared with reference proteins. Under simulated conditions, highest digestion was found for whey protein, followed by soy, pea, HMW, casein and LMW.

Phosphatidic acid plays a special role in stabilizing and folding of the tetrameric potassium channel KcsA.

In this study, we investigated how the presence of anionic lipids influenced the stability and folding properties of the potassium channel KcsA. By using a combination of gel electrophoresis, tryptophan fluorescence and acrylamide quenching experiments, we found that the presence of the anionic lipid phosphatidylglycerol (PG) in a phosphatidylcholine (PC) bilayer slightly stabilized the tetramer and protected it from trifluoroethanol-induced dissociation. Surprisingly, the presence of phosphatidic acid (PA) had a much larger effect on the stability of KcsA and this lipid, in addition, significantly influenced the folding properties of the protein.

2,2,2-Trifluoroethanol changes the transition kinetics and subunit interactions in the small bacterial mechanosensitive channel MscS.

2,2,2-Trifluoroethanol (TFE), a low-dielectric solvent, has recently been used as a promising tool to probe the strength of intersubunit interactions in membrane proteins. An analysis of inner membrane proteins of Escherichia coli has identified several SDS-resistant protein complexes that separate into subunits upon exposure to TFE. One of these was the homo-heptameric stretch-activated mechanosensitive channel of small conductance (MscS), a ubiquitous component of the bacterial turgor-regulation system.

Covalently dimerized SecA is functional in protein translocation.

The ATPase SecA provides the driving force for the transport of secretory proteins across the cytoplasmic membrane of Escherichia coli. SecA exists as a dimer in solution, but the exact oligomeric state of SecA during membrane binding and preprotein translocation is a topic of debate. To study the requirements of oligomeric changes in SecA during protein translocation, a non-dissociable SecA dimer was formed by oxidation of the carboxyl-terminal cysteines.

Detection and identification of stable oligomeric protein complexes in Escherichi coli inner membranes: a proteomics approach.

In this study we present a new technology to detect stable oligomeric protein complexes in membranes. The technology is based on the ability of small membrane-active alcohols to dissociate the highly stable homotetrameric potassium channel KcsA. It is shown via a proteomics approach, using diagonal electrophoresis and nano-flow liquid chromatography coupled to tandem mass spectrometry, that a large number of both integral and peripheral Escherichia coli inner membrane proteins are part of stable oligomeric complexes that can be dissociated by small alcohols.

Distinct conformational stability and functional activity of four highly homologous endonuclease colicins.

The family of conserved colicin DNases E2, E7, E8, and E9 are microbial toxins that kill bacteria through random degradation of the chromosomal DNA. In the present work, we compare side by side the conformational stabilities of these four highly homologous colicin DNases. Our results indicate that the apo-forms of these colicins are at room temperature and neutral pH in a dynamic conformational equilibrium between at least two quite distinct conformers.

Photo-crosslinking analysis of preferential interactions between a transmembrane peptide and matching lipids.

In this study, a novel method is presented by which the molecular environment of a transmembrane peptide can be investigated directly. This was achieved by incorporating a photoactivatable crosslinking probe in the hydrophobic segment of a model transmembrane peptide. When this peptide was incorporated into lipid bilayers and irradiated with UV light, a covalent bond was formed between the crosslinking probe and a lipid.

Membrane interaction of the glycosyltransferase MurG: a special role for cardiolipin.

MurG is a peripheral membrane protein that is one of the key enzymes in peptidoglycan biosynthesis. The crystal structure of Escherichia coli MurG (S. Ha, D.