Studies on the Effect of Salts on the Channel Activity of Kissper, a KiwiFruit Peptide

摘要

Fruits and vegetables are known to possess health benefits: indeed, they contain a large number of bioactivemolecules with a positive impact on human health. Dietary proteins possess specific biological properties which makethese components potential ingredients of functional or health-promoting foods. Many of these properties are attributed tophysiologically-active peptides encrypted in protein molecules.Kissper, a 39-residue peptide isolated from kiwi fruit (Actinidia deliciosa), derives from the processing of kiwellin,a well-represented novel allergenic protein present in the edible part of the fruit. Kissper has six cysteine residuesforming three disulfide bridges. This cysteine pattern is similar, but not identical, to those observed in some plant andanimal proteins, including toxins involved in defence mechanisms. We show that kissper forms ion channels inDOPS:DOPE:POPC PLMs in different media, such as KCl, potassium gluconate, potassium citrate and potassiumphosphate monobasic. Kissper$s channels show a strong voltage dependence in all media used, and an estimated porediameter in the range from 1.9 to 7.6 ? in KCl medium. Finally, kissper$s pores shift selectivity from anions to neutral tocations, depending on the nature of the salt solutions. Therefore we propose the kissper as a novel nutraceuticalcomponent of kiwi fruit that may have a positive impact on human health due to its channel-like pathways whichmodulate membrane permeability. The kissper action might promote the adsorption of substances, in particular, within thegastrointestinal tract, helping digestion, preventing constipation and harmful accumulation of metabolites.