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Interaction Study and Reactivity of Zr IV ‐Substituted Wells–Dawson Polyoxometalate towards Hydrolysis of Peptide Bonds in Surfactant Solutions
Author(s) -
Quanten Thomas,
Shestakova Pavletta,
Van Den Bulck Dries,
Kirschhock Christine,
ParacVogt Tatja.
Publication year - 2016
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201503976
Subject(s) - chemistry , pulmonary surfactant , sodium dodecyl sulfate , polyoxometalate , hydrolysis , bromide , inorganic chemistry , nuclear magnetic resonance spectroscopy , dipeptide , cationic polymerization , medicinal chemistry , peptide , nuclear chemistry , organic chemistry , catalysis , biochemistry
The interaction between the 1:2 Zr IV :Wells–Dawson complex, K 15 H[Zr(α 2 ‐P 2 W 17 O 61 ) 2 ] ( 1 ), and a range of surfactants was studied in detail with the aim of developing metal‐substituted POMs as potential artificial proteases for membrane proteins. The surfactants include the positively charged cetyl(trimethyl)ammonium bromide (CTAB), the negatively charged sodium dodecyl sulfate (SDS), the neutral Triton X‐100 (TX‐100), and zwitterionic 3‐[dodecyl(dimethyl)ammonio]‐1‐propanesulfonate (Zw3‐13) and 3‐[dimethyl(3‐{[(3α,5β,7α,12α)‐3,7,12‐trihydroxy‐24‐oxocholan‐24‐yl]amino}propyl)ammonio]‐1‐propanesulfonate (CHAPS). A combination of multinuclear 1 H, 13 C, and 31 P NMR spectroscopy, 1 H diffusion‐ordered NMR spectroscopy ( 1 H DOSY), and nuclear Overhauser effect spectroscopy (NOESY) was used to examine the interaction between 1 and each surfactant on the molecular level. Cationic surfactant CTAB caused precipitation of 1 due to strong electrostatic interactions, while the anionic SDS and neutral TX‐100 surfactants did not exhibit any interaction at neutral pD. 1 H DOSY NMR spectroscopy indicated an interaction between 1 and zwitterionic surfactants Zw3‐12 and CHAPS, which occurs via the positively charged ammonium group in the surfactant molecule. In the presence of anionic, neutral, and zwitterionic surfactants, 1 preserves its catalytic activity towards the hydrolysis of the peptide bond in the dipeptide glycyl‐ l ‐histidine (GH). The fastest hydrolysis was observed at pD 7.0 and could be rationalized by taking into account pD‐dependent speciation of 1 and coordination properties of GH.