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Zervamicin IIB is a 16 amino acid peptaibol that forms voltage dependent ion channels with multilevel conductance states in planar lipid bilayers and vesicular systems. Stability of the hinge region and intermolecular interactions were investigated in the N- and C-terminally spin-labelled peptide analogues. Intermolecular and intramolecular paramagnetic enhancement indicates that zervamicin behaves as a rigid helical rod in methanol solution. There are no high amplitude hinge-bending motions, and the peptaibol is monomeric up to concentration 1.5 mM. Stability of the hinge region illustrates the helix stabilising propensity of the Pro residue in membrane mimic environments and implies absence of significant conformational rearrangement due to voltage peptaibol activation.

The effect of dynamic axial compression within a range of up to 5 bar upon the structure of the bed packed with soft and semi-rigid packing materials (Sephadex G-25, Bio-Gel P2 and Toyopearl HW-40) and the associated chromatographic parameters were studied for size exclusion chromatography. Continuous packing compression is accomplished by use of a special column with controlled external pressure applied to the packing. Compression has been shown to favor an overall increase in the resolution with pressure optima observed in some cases.

Three 18-membered analogues of the N-terminal fragment of the sarcotoxin IA cationic antimicrobial peptide were synthesized by the solid phase method of peptide synthesis with the use of swellographic monitoring. The ability of these peptides to inhibit the growth of various bacteria in culture medium and their hemolytic activity in experiments on human erythrocytes were studied. The analogue completely corresponding to the N-terminal amino acid sequence of the natural sarcotoxin IA with the amide group on its C-terminus exhibited higher antibacterial activity. The presence of carboxyl group on the C-terminus or the substitution of Tyr for Trp2 resulted in a decrease in the antimicrobial activity of the peptide. Our results indicate that the amphiphilic N-terminal peptide corresponding to the 1-18 sequence of sarcotoxin IA involves the moieties responsible for the antimicrobial activity of the antibiotic.

We describe the noninvasive real-time pressure monitoring of Boc- and Fmoc-based peptide synthesis. Pressure was measured using a resistance strain gauge attached to the inlet of a continuous-flow reactor of variable volume. In the assembly of the 'difficult' polyalanine sequence, it was shown that pressure monitoring can reveal structural variations of the peptide-resin, e.g. the onset, development and termination of aggregation. This method provided washing minimization that favored substantial saving of solvents. The obtained results demonstrated the advantage of pressure monitoring over swellographic monitoring.

It has been demonstrated that SPPS with Boc amino group protection can be monitored spectrophotometrically if it is performed in a continuous-flow reactor of variable volume. It is shown that this approach provides useful and adequate evidence on the beginning/end-point of most steps of the SPPS cycle. At the deprotection step the spectrophotometric monitoring enables real-time recording of the initial and final moments of the process. When synthesizing a 'difficult' polyalanine sequence, we were able to monitor variation in the deprotection dynamics associated with the aggregation phenomena. The time actually necessary for the Boc protecting group removal appeared to be significantly smaller than that usually preset in the available Boc-SPPS protocols.

An automatic modular SynChrom system was designed for solid phase synthesis and chromatographic purification of peptides. Structural constituents and organization and operation of the system in solid phase peptide synthesis and liquid column chromatography modes are described. Swellographic monitoring of the course of synthesis was used. Hydraulic diagrams, operation algorithm and software description are presented.

Automatic solid phase peptide synthesis using the SynChrom system is described. Problems of swellographic monitoring are discussed. Combined monitoring (swellographic, spectrophotometric, and manometric) of all steps of the synthetic cycle are suggested. Potential applications of the system to liquid column chromatography were demonstrated.

The protocol for solid phase peptide synthesis using automatic synthesizers MilliGen/Biosearch 9500 and 9600 with built-in variable volume flow-reactors has been elaborated. The data of swellographic monitoring were used for optimization of process parameters. The peptides involving from 10 to 21 amino acid residues were synthesized using developed protocol. Significant economy of reagents and solvents has been demonstrated for synthesis of good quality peptides.

A new type of practical low pressure continuous-flow reaction system has been developed, allowing continuous "dead volume free" handling of polystyrene-based peptide-resins (PR) under conventional Boc/Bzl solid-phase peptide synthesis (SPPS). The reaction system offers a unique opportunity for direct recording of bed volume changes accompanying chemical and physical manipulations with PRs. A new monitoring principle, called "swellography," based on a straightforward interpretation of PR bed volume dynamics, is described. It seems to provide a basis for a novel, automated, non-invasive feedback control system. This novel technique does not complicate SPPS practice; and, moreover, it provides useful information about the swelling behavior of PRs in the real time of SPPS. Although the approach is not directly applicable for quantitation of deprotection and coupling reactions, it does give a good opportunity for real-time optimization of solvent and re-agent usage during the washing and neutralization steps of SPPS. A number of 8- to 16-membered peptides were synthesized manually with complete swellographic monitoring. The practical merits of the new approach are discussed in some detail.