Interaction of Vanadyl (VO²⁺) with Ligands Containing Serine, Tyrosine, and Threonine

Abstract

Reaction of vanadyl sulfate with an aldehyde (2-hydroxy-1-naphthaldehyde (nap); 3-methoxysalicylaldehyde = o-vanillin (van)) and an amino acid carrying an OH group (L-tyrosine (L-tyr); L-serine (L-ser), L-threonine (L-thr)) yielded the complexes [VO(nap-D-Tyr)(H2O)] 1a, [VO(van-D,L-Tyr)(H2O)] 1c, [VO(nap-Ser)(H2O)] 2a, [VO(van-D,L-Ser)(H2O)] 2b, [VO(nap-Thr)(H2O)] 3a, and [VO(van-Thr)(H2O)] 3b. [VO(nap-L-tyr(H2O)], 1b, was obtained from the reaction between [VO(nap)(2)] and l-TyrOMe. The crystal and molecular structures of 1a.CH3OH, 1b.CH3OH, 1c.H2O, 2b.2H2O, and the Schiff base nap-D,L-TyrOMe (4) are reported. The ligands coordinate in a tridentate manner through the phenolate component of nap or van, the imine nitrogen, and the carboxylate of the amino acid. Direct coordination of the (deprotonated) OH amino acid functionality is not observed in these complexes. Instead, the OH groups are involved in hydrogen bonding, leading, along with pi-pi stacking, to extended one- and three-dimensional supramolecular networks. The relevance for the interaction between oxovanadium(IV,V) and proteins having serine, threonine, or tyrosine at their reactive sites is addressed.

Supramolecular assembly of a new series of copper-l-arginine Schiff bases

“…34 In this work, HRNap was obtained in high yield (94%), following a simpler method reported by Chow and Ebel. 36,37 Typically, an amino acid Schiff base with an o-hydroxyaryl moiety enables its isolation due to intramolecular stabilization by hydrogen bonding. 34 As an attempt to elucidate the effect of para-substituent to -OH of hydroxyaryl, nitro and methyl are chosen as electron withdrawing and donating groups respectively.…”

Influence of Vanadium Compounds on Cellular Functions

“…ENDOR reveals that, at the low-affinity site, the divalent metal ion is exclusively in an oxygen-functional coordination sphere. 91 In any case, the role of vanadate as an oxidation catalyst is in accord with its common use in oxidation processes not related to biochemical events. If the myosin subfragment 1 is irradiated with UV light in the presence of vanadates, cleavage occurs and vanadate is reduced to vanadyl, which is not active as an energy transmitter in photo-cleavage.…”

Lipid-bilayer-mimicking solid-state structures of Cu(ii) and Ni(ii) with l-tryptophan and l-tyrosine Schiff base derivatives

“…The second ligand in this study, Na 2 YNap, was prepared similarly to that reported by Rehder and co-workers, but with no esterification of the carboxylate group. 34 Complexation of these Schiff bases with M (II) (M ¼ Ni, Cu) is shown in Scheme 1. The Ni(II) complex 3 was prepared in a one-pot reaction in which the ligand was formed in situ.…”