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Stereochemistry of insect kinin tetrazole analogues and their diuretic activity in crickets.

100%

Nachman R. J., Coast G. M., Kaczmarek K., Williams H. J., Zabrocki J.

Acta Biochimica Polonica

2004

vol. 51

issue 1

121-127

Insect kinin analogues of the sequence Phe-Phe-ψ[CN4]-Ala-Trp-Gly-NH2 containing (L-Phe2,L-Ala3) and (L-Phe2,D-Ala3) stereochemical variants of the tetrazole moiety, a mimic of the type VI β-turn, demonstrate significant agonist and partial antagonist activity, respectively, in a cricket diuretic bioassay. A comparison of the solution conformations of these two stereochemical variants indicates a structural basis for their divergent bioactivities. The (D-Phe2,D-Ala3) stereochemical variant was synthesized and found to demonstrate significant agonist activity. The results further define stereochemical requirements for the diuretic activity of insect kinins in crickets and provide valuable information for the design of biostable analogues capable of disrupting digestive and diuretic processes in pest insects.

Chelating ability of proctolin tetrazole analogue

86%

Łodyga-Chruścińska E., Sanna D., Micera G., Chruściński L., Olejnik J., Nachman R. J., Zabrocki J.

Acta Biochimica Polonica

2006

vol. 53

issue 1

65-72

The aim of the investigation was to establish the chelating ability of a new proctolin analogue of the sequence Arg-Tyr-LeuΨ[CN4]Ala-Thr towards copper(II) ions. The insertion of the tetrazole moiety into the peptide sequence has considerably changed the coordination ability of the ligand. Potentiometric and spectroscopic (UV-Vis, CD, EPR) results indicate that the incorporation of 1,5-disubstituted tetrazole ring favours the formation of a stable complex form of CuH-1L. This 4N coordination type complex is the dominant species in the physiological pH range. The tetrazole moiety provides one of these nitrogens. The data indicate that Cu(II) ions are strongly trapped inside the peptide backbone. These findings suggest that Cu(II) can hold peptide chains in a bent conformation. This bent conformation may be essential for bioactivity of the tetrazole peptides.

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2 Acta Biochimica Polonica

1 2006

1 2004

2 Nachman R. J.

2 Zabrocki J.

1 Chruściński L.

1 Coast G. M.

1 Kaczmarek K.

1 Micera G.

1 Olejnik J.

1 Sanna D.

1 Williams H. J.

1 Łodyga-Chruścińska E.

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Stereochemistry of insect kinin tetrazole analogues and their diuretic activity in crickets.

Chelating ability of proctolin tetrazole analogue