Syntheses of methyl-devinylporphyrins related to protoporphyrin-IX. Initial studies on the mechanism of the copper (II) catalysed cyclization of 1′,8′-dimethyl-a,c-biladiene salts

Solution NMR study of environmental effects on substrate seating in human heme oxygenase: Influence of polypeptide truncation, substrate modification and axial ligand

“…1) was purchased from Frontier Chemicals; 2,4-dimethylprotoporphyrin-IX, DMDH ( Fig. 1 with R = methyl), was purchased from Mid-Century Chemicals and the iron inserted by standard procedures [35]. The 1:1 molar equivalents of the substrate was titrated into apo-hHO and $20 mM apo-hHO* solution buffered at pH 7.0-8.0 with phosphate in either the absence or presence of $20 M KCN.…”

Solution NMR Characterization of an Unusual Distal H-bond Network in the Active Site of the Cyanide-inhibited, Human Heme Oxygenase Complex of the Symmetric Substrate, 2,4-Dimethyldeuterohemin

“…2,4-Dimethyldeuteroporphyrin was purchased from Mid-Century Chemicals and the iron incorporated to yield DMDH by standard procedures (36). DMDH was titrated into apo-hHO to a 1:1 stoichiometry in the presence of a 10-fold molar excess of KCN in a 90% , using the heme for the ␣-meso-H for H* (R* Fe ϭ 4.6Å and T 1 * ϭ 50 ms) as reference.…”

“…Such a complex can serve as the reference for future solution NMR structural studies of hHO mutants, apo-hHO, and the ligand-free hHO-substrate complex, as well as for other natural genetic variants such as the bacterial HOs (33)(34)(35). The symmetric hemin, 2,4-dimethyldeuterohemin (36), DMDH ( Fig. 1 with R ϭ CH 3 ), provides a single species with narrower resonances than with protohemin, and thereby allows significantly more extensive and definitive assignments as well as structural characterization of residues in the substrate-binding cavity.…”

Solution 1H NMR Investigation of the Active Site Molecular and Electronic Structures of Substrate-bound, Cyanide-inhibited HmuO, a Bacterial Heme Oxygenase fromCorynebacterium diphtheriae

“…PH was purchased from Sigma. 2,4-Dimethyldeuteroporphyrin was purchased from Mid-Century Chemicals, and the iron was incorporated to yield DMDH by standard procedures (25). PH and DMDH were titrated into apo-hHO to a 1:1 stoichiometry in the presence of a 10-fold molar excess of KCN in a 90% H 2 O and 10% 2 H 2 O solution buffered at pH 7.4 with 100 mM phosphate.…”

“…Two-dimensional 1 H NMR of a hHO complex with the 2-fold symmetric substrate 2,4-dimethyldeuterohemin (DMDH; R ϭ CH 3 in Fig. 1) (25) allowed sufficiently definitive and extensive assignments to identify (21) an unusual distal H-bond networks involving some extremely strong H-bonds (labile proton shifts between 17 and 10 ppm) whose acceptor could be identified in the hHO⅐PH⅐H 2 O crystal structure (15). Moreover, it was demonstrated that water molecules were in the immediate vicinity (ϳ3 Å) of each of the strong H-bond donors (22).…”