title: 3-hydroxybenzene 1,2,4-trisphosphate, a novel second messenger mimic and unusual substrate for type-I myo-inositol 1,4,5-trisphosphate 5-phosphatase: Synthesis and physicochemistry.
abstract: 3-Hydroxybenzene 1,2,4-trisphosphate 4 is a new myo-inositol 1,4,5-trisphosphate analogue based on the core structure of benzene 1,2,4-trisphosphate 2 with an additional hydroxyl group at position-3, and is the first noninositol based compound to be a substrate for inositol 1,4,5-trisphosphate 5-phosphatase. In physicochemical studies on 2, when three equivalents of protons were added, the (31)P NMR spectrum displayed monophasic behaviour in which phosphate-1 and phosphate-2 behaved independently in most of the studied pH range. For compound 4, phosphate-2 and phosphate-4 interacted with the 3-OH group, which does not titrate at physiological pH, displaying complex biphasic behaviour which demonstrated co-operativity between these groups. Phosphate-1 and phosphate-2 strongly interacted with each other and phosphate-4 experienced repulsion because of the interaction of the 3-OH group. Benzene 1,2,4-trisphosphate 2 is resistant to inositol 1,4,5-trisphosphate type I 5-phosphatase catalysed dephosphorylation. However, surprisingly, 3-hydroxybenzene 1,2,4-trisphosphate 4 was dephosphorylated by this 5-phosphatase to give the symmetrical 2,3-dihydroxybenzene 1,4-bisphosphate 16. The extra hydroxyl group is shown to form a hydrogen bond with the vicinal phosphate groups at -15 degrees C, and (1)H NMR titration of the ring and hydroxyl protons in 4 shows the OH proton to be strongly stabilized as soon as the phosphate groups are deprotonated. The effect of the phenolic 3-OH group in compound 4 confirms a critical role for the 6-OH group of the natural messenger in the dephosphorylation mechanism that persists even in radically modified analogues.
authors.affiliation: Wolfson Laboratory of Medicinal Chemistry, Department of Pharmacy and Pharmacology, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Mills
authors.forename: Hélène
authors.initials: H
authors.lastname: Dozol
authors.forename: Fabrice
authors.initials: F
authors.lastname: Vandeput
authors.forename: Katrien
authors.initials: K
authors.lastname: Backers
authors.forename: Timothy
authors.initials: T
authors.lastname: Woodman
authors.forename: Christophe
authors.initials: C
authors.lastname: Erneux
authors.forename: Bernard
authors.initials: B
authors.lastname: Spiess
authors.forename: Barry V L
authors.initials: BV
authors.lastname: Potter
mesh_terms: D055598:Chemical Phenomena; D002627:Chemistry, Physical; D006863:Hydrogen-Ion Concentration; D000072181:Inositol Polyphosphate 5-Phosphatases; D009682:Magnetic Resonance Spectroscopy; D018716:Molecular Mimicry; D015394:Molecular Structure; D010755:Organophosphates / Q000138:chemical synthesis* / Q000737:chemistry / Q000378:metabolism*; D010710:Phosphates / Q000737:chemistry; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism*; D010766:Phosphorylation; D011122:Polyphosphates / Q000737:chemistry; D011522:Protons; D012394:Rosaniline Dyes / Q000737:chemistry / Q000378:metabolism; D015290:Second Messenger Systems; D013379:Substrate Specificity; D017186:Titrimetry
chemical_list: C515727:3-hydroxybenzene 1,2,4-trisphosphate; D010755:Organophosphates; D010710:Phosphates; D011122:Polyphosphates; D011522:Protons; D012394:Rosaniline Dyes; C005095:malachite green; D010744:Phosphoric Monoester Hydrolases; D000072181:Inositol Polyphosphate 5-Phosphatases