Proteins melittin

In this section, we review our first examinations of tryptophan probing sensitivity and water dynamics in a series of important model systems from simple to complex, which range from a tripeptide [70], to a prototype membrane protein melittin [70], to a common drug transporter human serum albumin [71], and to lipid interface of a nanochannel [86]. At the end, we also give a special case that using indole moiety of tryptophan probes supramolecule crown ether solvation, and we observed solvent-induced supramolecule folding [87]. The obtained solvation dynamics in these systems are linked to properties or functions of these biological-relevant macromolecules. 

Figure 3.12 SLD profiles obtained for a hybrid bilayer in the absence (black curve) and in the presence (grey curve) of the protein melittin. The experimental NR curves used to generate the SLD profiles are shown in the inset (taken from [53]). Figure taken from [40].

Pierce and Boxer [102] have described Stark effects on IV-acetyl-L-tryptophanamide and the single tryptophan residue in the protein melittin. They separated effects on the Lj, and bands by taking advantage of the different fiuorescence anisotropy of the two bands (Sect. 5.6). In agreement with Fig. 4.27, the La band exhibited a relatively large Afi of approximately 6 fT>ehye, where/is the unknown local-field correction factor. The Aji for the Lb band was much smaller. 

Greater insight into the specific interactions that anchor and stabilize membrane-bound proteins can be gleaned from the simulation study of the protein melittin in a DMPC membrane [109]. Melittin is the major protein component of bee venom that is responsible for the lysis (opening) of the cell membrane. It is twenty-six residues long with the sequence GIGAVLKVLTTGLPALIS WIKRKRQQ. 

GTP gamma S binding proteins from membranes of porcine brain Purification, comparison with conventional column Anion Exchange and Affinity (Melittin) disks [82]... 

On the other hand, basic myelin protein and monomeric melittin are proteins which, by many criteria, are devoid of ordered structure in aqueous solutions. This results in freedom of rotation of tryptophan residues which are exposed to the solvent. Such a situation may exist for peptides without regular structure and for denatured proteins. 

Figure 2.10. The dependence of the position of the fluorescence spectrum maximum on excitation wavelength for 2,6-TNS in model media (a) and in complexes with proteins (b). (a) 2,6-TNS (3 x 10-s) M in glucose glass at 20°C (1), glycerol at +1°C (2), and 80% aqueous ethanol at 20°C (3). Excitation spectra are for glycerol (4) and 80% ethanol (5). (b) 2,6-TNS in complexes with / -lactoglobulin (1), tetrameric melittin (2), human serum albumin (3), and lysozyme (4) at 20°C. Excitation spectrum (5) is for human serum albumin.

Figure 2.11. The dependence of the position of the fluorescence spectrum maximum on excitation wavelength for tryptophan in a model medium (glycerol) at different temperatures (a) and singletryptophan proteins (b). 1, Whiting parvalbumin, pH 6.S in the presence of Ca2+ ions 2, ribonuclease Th pH 6.5 3, ribonuclease C2, pH 6.5 4, human serum albumin, pH 7.0, +10"4 M sodium dodecyl sulfate 5, human serum albumin, pH 3.2 6, melittin, pH 7.5, +0.15 M NaCl 7, protease inhibitor IT-AJ from Actinomyces janthinus, pH 2.9 8, human serum albumin, pH 7.0 9, -casein, pH 7.5 10, protease inhibitor IT-AJ, pH 7.0 11, basic myelin protein, pH 7.0 12, melittin in water. The dashed line is the absorption spectrum of tryptophan.

CaM), of fatty acid carboxylate to intestinal fatty acid binding protein (IFABP), and of peptides (e.g, melittin) to Ca +-saturated calmodulin (holo CaM)]. We also extended PLIMSTEX to protein-protein interactions involving self associations of various insulins [33]. These are widely studied systems, and their individual K values range from to 10 M h... 

Fig. n.7 Sharp-break PLIMSTEX curves at high protein concentration [23], Line (a) melittin (a 26-amino-acid peptide) titration. Line (b) mastoparan (a 16-amino-acid peptide) titration of 15 pM Ca +-saturated porcine calmodulin (CaM-4Ca) in 50 mM HEPES, 100 mM KCI, 0.49 mM Ca +, 99% D2O, apparent pH 7.4. Data points are based on the average of t /o runs for each titration system, and the breaking point clearly indicates 1 1 protein-ligand binding stochiomet. ... 

Molecular biology melittin/ Sigma 2000 protein/binding to calmodulin/reagent for protein analysis hon bee (Apis mellifera (L.), Ins. voiom... 

Anionic peptides are almost inactive in the presence of serum because they have the disadvantage of binding to serum proteins. Amphiphilic basic peptides, such as melittin (GIGAVLKVLTTGLPALISWIKRKRQQ-NH2), isolated from the venom of the European honey bee Apis mellifera (Dempsey, 1990) and K5, the... 

Baudier J, Mochly-Rosen D, Newton A, Lee SH, Koshland DE, Jr., Cole RD. 1987. Comparison of SlOOb protein with calmodulin interactions with melittin and microtubule-associated tau proteins and inhibition of phosphorylation of tau proteins by protein kinase C. Biochemistry 26(10) 2886-2893. 

Pawlak, M., Meseth, U., Dhanapal. B Mutter, M., and Vogel, H. (1994) Template-assembled melittin Structural and functional characterization of a designed, synthetic channel-forming protein. Protein Sci. 3,1788-1805. 

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