Chemotaxis induced by SXWS tetrapeptides in Tetrahymena—overlapping chemotactic effects of SXWS sequences and their identical amino acids

Abstract

The chemotactic potential of SXWS peptides and the components of the extracellular domain of cytokine receptors were investigated in Tetrahymena as a functional index of substitution with different amino acids in the position 'X' of the tetrapeptide. Data obtained demonstrate that position X plays a special determining role in the ligand, SEWS and STWS possess extremely strong chemoattractant ability, and aromatic amino acids result in chemorepellent ligands. Diverse effects of structurally related molecules, for example, SNWS-SDWS, demonstrate a highly sensitive discrimination potential in the applied model system. Physicochemical characteristics (hydropathy, residue size, and solvent-exposed area) of the amino acids were correlated with the chemotactic activity. Data obtained by computer-assisted conformation analysis of SXWS peptides and the highly overlapping chemotactic effects of the investigated SXWS peptides as well as the presence of the amino acids in the 'X' position indicate that member 'X' of the SXWS sequence performs a special role in interactions with the chemotaxis receptors in the membrane.

Effect of SXWS/WSXWS peptides on chemotaxis and adhesion of the macrophage‐like cell line J774

“…According to data of literature, chemoattractant ligands can take their effect in a wide concentration range, whereas the concentration range of the effect in the case of neutral or chemorepellent ligands is usually narrower. Our results show a good correlation with former observations on T. pyriformis (Kőhidai et al , ; Láng et al , ). The most effective chemoattractant tetrapeptide (SMWS) elicited an effect in the widest range (100–250%), and other chemoattractant tetrapeptides such as SQWS (100–141%), SAWS (59–134%) and SSWS (96–141%) elicited an effect also in a relatively wide range.…”

“…Structural properties of a tetrapeptide library with SXWS sequence, where X position was substituted with all proteinogenic amino acids except cystein, were studied earlier (Láng et al, ) . It has been established that most of the tetrapeptides (except X = Gly, Pro or Arg) have a non‐flexible conformation stabilized by a characteristic H‐bond pattern, from which the X residue emerges and has no significant influence on the conformation of the whole peptide.…”