Recent advances in the understanding of the biological chemistry of manganese.

Developments in manganese biochemistry have centered on the discovery of new manganese enzymes, X-ray analysis of binuclear manganese enzymes, and the discovery of new spectroscopic signatures for the oxygen-evolving complex. Despite these gains, many questions regarding the structure, composition and redox state of the oxygen-evolving complex remain unanswered.

The role of protonation and metal chelation preferences in defining the properties of mercury-binding coiled coils.

To define the delicate interplay between metal chelation, protein folding and function in metalloproteins, a family of de novo-designed peptides was synthesized that self-assemble in aqueous solution to form two and three-stranded alpha-helical coiled coils. Each peptide contains a single Cys residue at an a or d position of the heptad repeat. Peptide association thus produces a Cys-rich coordination environment that has been used to bind Hg(II) ions.

The [Mn(2)(2-OHsalpn)(2)](2-,-,0,+) System: Synthesis, Structure, Spectroscopy, and Magnetism of the First Structurally Characterized Dinuclear Manganese Series Containing Four Distinct Oxidation States.

The series of complexes [Mn(2)(2-OH(Xsal)pn)(2)](2-,-,0,+) [where 2-OH(Xsal)pn represents substituted-phenyl-ring derivatives (X = H, 5-Cl, 3,5-Cl(2), 5-NO(2)) of 1,3-bis(salicylideneamino)-2-propanol] allow for the first detailed structural, magnetic, and spectroscopic study of a series of complexes that are the most active functional models for the manganese catalases. Representative examples of each oxidation state of the series (mimicking all of the known oxidation states for the enzyme's reaction chemistry) have been crystallographically characterized. The molecules presented herein are described as symmetric derivatives because they form dimers with both of the ligands spanning both Mn ions with the alkoxide on the backbone of the ligand bridging the metals.

Alteration of interleukin-2 (IL-2) and soluble IL-2 receptor secretion in the sera and urine of patients with rickettsial boutonneuse fever.

Sera and urine samples from 115 Sicilian patients with boutonneuse fever (BF), obtained at the time of diagnosis and after clinical recovery, were analyzed for concentrations of interleukin (IL)-2 and soluble IL-2 receptor (sIL-2R). There were significantly high levels of sIL-2R in the urine and sera of patients with acute BF compared with healthy controls, and the values returned to normal following successful chemotherapy. The data indicate that the sIL-2R urine concentrations correlated directly with the sIL-2R sera levels.

In vitro analysis of the interaction between sucralfate and ketoconazole.

In healthy volunteers, the bioavailability of ketoconazole is significantly decreased during simultaneous administration with sucralfate. In an effort to address this problem, we examined the interaction between sucralfate and ketoconazole in aqueous solutions and in simulated gastric fluid (SGF) at various initial pHs (1, 2, 3, and 6) in the presence or absence of glutamic acid hydrochloride (GA). Samples from each solution were taken 30 min and 2 h after the addition of ketoconazole to evaluate the solubility of ketoconazole over the usual time period of maximal absorption of ketoconazole in humans.

The effect of protonation on [Mn(IV)(μ2-O)] 2 complexes.

The series of complexes [Mn(IV)(X-SALPN)(μ2-O)]2, 1: X=5-OCH3; 2: X=H; 3: X=5-Cl; 4: X=3,5-diCl; 5: X=5-NO2, contain [Mn2O2](4+) cores with Mn-Mn separations of 2.7 Å. These molecules can be protonated to form [Mn(IV)(X-SALPN)(μ2-O,OH)]2 (+) in which a bridging oxide is protonated.

Solution structure of Fe(II) cytochrome c551 from Pseudomonas aeruginosa as determined by two-dimensional 1H NMR.

The solution structure of Fe(II) cytochrome c551 from Pseudomonas aeruginosa based on 2D 1H NMR data is reported. Two sets of structure calculations were completed with a combination of simulated annealing and distance geometry calculations: one set of 20 structures included the heme-peptide covalent linkages, and one set of 10 structures excluded them. The main-chain atoms were well constrained within the two structural ensembles (1.

Sequential 1H NMR assignments of iron(II) cytochrome c551 from Pseudomonas aeruginosa.

Sequence-specific 1H NMR resonance assignments for all but the C-terminal Lys 82 are reported for iron(II) cytochrome c551 from Pseudomonas aeruginosa at 25 degrees C and pH = 6.8. Spin systems were identified by using TOCSY and DQF-COSY spectra in 2H2O and 1H2O.

Copper-induced expression, cloning, and regulatory studies of the plastocyanin gene from the cyanobacterium Synechocystis sp. PCC 6803.

Plastocyanin can be detected in Synechocystis sp. PCC 6803 when 3 microM copper is added to the growth medium, BG-11. The plastocyanin gene (petE) was cloned from a genomic lambda EMBL 3 library by screening with the petE gene from Anabaena sp.

Structural characterization of the manganese(IV) Schiff-base complex MnIV(5-Cl-SALAHP)2.

Bis[3-(5-chlorosalicylideneamino)propanolato-O,N,O']manganes e(IV) methanol solvate, [Mn(C10H10ClNO2)2].CH3OH, Mr = 510.3, monoclinic, P2(1)/c, a = 11.

[Cryptococcosis. Apropos of a case].

A case of cryptococcosis in a woman 46 years old, with lesions of the skin and the lung with an evolution of six years who answered satisfactory to a treatment with ketoconazole. We will discuss the duration of the lesion, the possible start of the skin aspect of the disease and the excellent response obtained with ketoconazole.

Determination of the screw sense specificity of bovine liver fructokinase.

Fructokinase from beef liver showed a clear reversal in specificity when the two isomers of ATP beta S were used as substrates with Mg2+ and Cd2+, with the Sp isomer having the higher V/K value with Mg2+ and the Rp isomer the higher value with Cd2+. The delta isomer of MgATP is thus the active form of the substrate. The substitution of sulfur for oxygen in the noncoordinated position of the beta-phosphate caused a 102-fold decrease in V/K over the value seen with MgATP, while substitution in the coordinated position gave a 21-fold decrease over the V/K value seen with CdATP.

Stability constants of Mg2+ and Cd2+ complexes of adenine nucleotides and thionucleotides and rate constants for formation and dissociation of MgATP and MgADP.

Stability constants for the Mg2+ and Cd2+ complexes of ATP, ADP, ATP alpha S, ATP beta S, and ADP alpha S have been determined at 30 degrees C and mu = 0.1 M by 31P NMR. Besides being of the utmost importance for determining species distributions for enzymatic studies, these constants allow an estimation of the preference of Cd2+ for sulfur vs.

Investigation of substrate specificity of creatine kinase using chromium (III) and cobalt(III) complexes of adenosine 5'-diphosphate.

The specificity for substrate binding to creatine kinase for metal-nucleotide complexes of the type Cr-(H2O)4-n(NH3)nADP (where n = 0, 3, or 4) and Co-(H2O)4-m(NH3)mADP (for m = 3 or 4) has been investigated over the pH range 5.5-7.8 with the delta-alpha, beta-bidentate diastereoisomers.

[Anal manifestations of lichen planus].

Lichen planus (LP) is an entity endowed with a striking polimorphysm and with a diversity of topographic localizations. In spite of the diagnostic difficulties that the combination of these factors occasionally produce, the histopathology of the lesion is tipical and diagnostic. Our presentation seems to be justified since, to the best of our knowledge, the anal localization of the disease has not been reported and it is also rare.

Thermodynamic binding constants for gallium transferrin.

Gallium-67 is widely used as an imaging agent for tumors and inflammatory abscesses. It is well established that Ga3+ travels through the circulatory system bound to the serum iron transport protein transferrin and that this protein binding is an essential step in tumor localization. However, there have been conflicting reports on the magnitude of the gallium-transferrin binding constants.

Iron supply to Escherichia coli by synthetic analogs of enterochelin.

Synthetic analogs of enterochelin (enterobactin) were tested for their ability to support the growth of Escherichia coli K-12 under iron-limiting conditions. The cyclic compound MECAM [1,3,5-N.N'; N"-tris-(2,3-dihydroxybenzoyl)-triamino-methylbenzene] and its N-methyl derivative Me3MECAM promoted growth, whereas the 2,3-dihydroxy-5-sulfonyl derivatives MECAMS and Me3MECAMS were inactive.

Ferric ion sequestering agents: kinetics of iron release from ferritin to catechoylamides.

The removal of ferric ion from the iron storage protein ferritin to synthetic catechoylamide sequestering agents has been studied using visible spectroscopy at 487 nm. One ligand which has been investigated in detail is N,N',N' ',-tris(2,3-dihydroxy-5-sulfobenzoyl)-1,5,10-triazadecane (3,4-LICAMS), which octahedrally coordinates the metal ion via six phenolic oxygens. For some related catechoylamide chelates, the percentage of iron removed after 6 h has been determined.

The normal trichogram of pubic hair.

The parameters of the trichogram of the pubic hair were studied with a previously described technique. Measurements were made on males and on non-pregnant, pregnant and post-partum females. In males and non-pregnant females denisty and rate of growth steadily decrease with age.