The Insertion Behaviour of Wheat Puroindoline-a into Diacylgalactosylglycerol Films

The role of bile salts in digestion

“…The hydrophobic face of the BS can then rotate to come into closer contact with the interface, anchored by the ionic interaction with the headgroup to allow the interfacial packing to be higher and thus the interfacial tension lower than it would be capable of alone. This has been observed previously for membrane active proteins and peptides [42]. Whereabouts in the interface the BS locate themselves is not clear, but evidence using surface potential measurements found no significant change in molecular orientation of the phospholipid at the interface in the presence of BS [43], suggesting the BS remain associated with the headgroup rather than the tail.…”

Molecular genetics of puroindolines and related genes: regulation of expression, membrane binding properties and applications

“…The Trp residues as well as the basic amino acid residues interspersed between them, and the basic nature of the proteins in general, are proposed to be important for the lipid binding and membrane insertion properties of PINs (Kooijman et al 1997;Le Guerneve et al 1998). The Trps are shown to comprise the lipidbinding site (Kooijman et al 1997(Kooijman et al , 1998. Importantly, Kooijman et al (1997) showed that there are two types of interactions between PINs and membrane lipids: Plant Mol Biol (2008) 66:221-231 225 hydrophobic interactions between the Trp residues and lipid tails, and electrostatic interactions between the Arg/ Lys residues in the TRD and the phosphate headgroups of lipids.…”

“…The charge and nature of the polar headgroups of lipids as well as chain packing and acyl chain length appear to influence the exact location of PINA in membranes (Kooijman et al 1997;Le Guerneve et al 1998;Jing et al 2003), and the phenylalanine domain flanking the TRD (Marion et al 1994) may also have a stabilising effect on binding of PINs (Kooijman et al 1997). PINA appears able to penetrate lipid membranes more deeply than ns-LTPs, which have weaker, lipid interface-only binding (Kooijman et al 1998) and PINB, which has fewer Trp and basic residues in its TRD. Both PINA and PINB interact more with negatively charged phospholipids than with neutral ones and possibly insert deeper into the former (Dubreil et al 1997;Le Guerneve et al 1998), confirmed by studying the interactions between each of the PIN proteins and lipids purified from wheat flour (Biswas and Marion 2006).…”

“…Importantly, Kooijman et al (1997) showed that there are two types of interactions between PINs and membrane lipids: Plant Mol Biol (2008) 66:221-231 225 hydrophobic interactions between the Trp residues and lipid tails, and electrostatic interactions between the Arg/ Lys residues in the TRD and the phosphate headgroups of lipids. Essentially, the TRD is the most important region of PINs for interaction with lipids, with the size, shape and partitioning properties of the Trp residues influencing their membrane binding (Kooijman et al 1998;Le Guerneve et al 1998;Yau et al 1998;de Planque et al 1999;Schibli et al 2002;Jing et al 2003). The charge and nature of the polar headgroups of lipids as well as chain packing and acyl chain length appear to influence the exact location of PINA in membranes (Kooijman et al 1997;Le Guerneve et al 1998;Jing et al 2003), and the phenylalanine domain flanking the TRD (Marion et al 1994) may also have a stabilising effect on binding of PINs (Kooijman et al 1997).…”

Differences in surface behaviour of galactolipoids originating from different kind of wheat tissue cultivated in vitro

“…They noticed that both galactolipids form monolayers exhibiting a structure of homogeneous liquid-expanded phase in agreement with the high degree of double bonds in the acyl chains that limits molecular packing. Kooijman et al (1998) studied the influence of puroindoline-a (PINa) injected into the subphase on the MGDG monolayer. They found that injection of PIN-a caused an increase of galactolipid monolayer surface pressure.…”