A 4-hydroxybenzoate 3-hydroxylase mutant enables 4-amino-3-hydroxybenzoic acid production from glucose in Corynebacterium glutamicum.

Background: Microbial production of aromatic chemicals is an attractive method for obtaining high-performance materials from biomass resources. A non-proteinogenic amino acid, 4-amino-3-hydroxybenzoic acid (4,3-AHBA), is expected to be a precursor of highly functional polybenzoxazole polymers; however, methods for its microbial production have not been reported. In this study, we attempted to produce 4,3-AHBA from glucose by introducing 3-hydroxylation of 4-aminobenzoic acid (4-ABA) into the metabolic pathway of an industrially relevant bacterium, Corynebacterium glutamicum.

Efficient monoacylglycerol synthesis by carboxylesterase EstGtA2 from Geobacillus thermodenitrificans in a solvent-free two-phase system.

The present study investigated high-yield monoacylglycerol (MAG) synthesis by bacterial lipolytic enzymes in a solvent-free two-phase system. Esterification by monoacylglycerol lipase from Bacillus sp. H-257 (H257) required a high glycerol/fatty acid molar ratio for efficient MAG synthesis.

Control of Lanthanide Coordination Environment: Synthesis, Structure, and Oxygen-Sensitive Luminescence Properties of an Eight-Coordinate Tb(III) Complex.

Coordination environment of the Tb(3+) ion in oxygen-sensitive luminescent complexes can be successfully controlled through the size of alkyl substituents on ligands {((RMe)ArOH)4cyclen} (R = tBu or Me; cyclen = 1,4,7,10-tetraazacyclododecane); a newly prepared eight-coordinate complex 1(tBu) shows higher oxygen sensitivity (KSV = 17 600) and lower luminescence quantum yield (Φ = 0.67 under N2) than those of the previously reported seven-coordinate analogues 1(Me) and [{((MeMe)ArO)3tacn}Tb(III)(THF)] (KSV = 12 600 and 8300, Φ = 0.91 and 0.

A macrocyclic tetraamine bearing four phenol groups: a new class of heptadentate ligands to provide an oxygen-sensitive luminescent Tb(III) complex with an extendable phenol pendant arm.

This paper presents a 1,4,7,10-teraazacyclododecane-based tetrakis-phenol as a protonated ligand precursor and its oxygen-sensitive luminescent terbium(III) complex with an extendable phenol pendant arm (Φ = 0.91 under N2, Φ = 0.031 under air), in which the potentially N4O4-octadentate ligand unprecedentedly coordinates to the Tb(3+) ion in a N4O3-heptadentate fashion.

A highly luminescent and highly oxygen-sensitive Tb(III) complex with a tris-aryloxide functionalised 1,4,7-triazacyclononane ligand.

This communication presents a new terbium(III) complex that shows the highest luminescence quantum yield among the oxygen-sensitive lanthanide complexes (Φ = 0.91 under N2, Φ = 0.054 under air).

Biochemical characterization of psychrophilic Mn-superoxide dismutase from newly isolated Exiguobacterium sp. OS-77.

Many types of superoxide dismutases have been purified and characterized from various bacteria, however, a psychrophilic Mn-superoxide dismutase (MnSOD) has not yet been reported. Here, we describe the purification and the biochemical characterization of the psychrophilic MnSOD from Exiguobacterium sp. strain OS-77 (EgMnSOD).

Novel H2-oxidizing [NiFeSe]hydrogenase from Desulfovibrio vulgaris Miyazaki F.

[NiFeSe]hydrogenases are promising biocatalysts in H2-based technology due to their high catalytic activity and O2-stability. Here, we report purification and characterization of a new membrane-associated [NiFeSe]hydrogenase from Desulfovibrio vulgaris Miyazaki F ([NiFeSe]DvMF). The [NiFeSe]DvMF was composed of two subunits, corresponding to a large subunit of 58.

Model study of CO inhibition of [NiFe]hydrogenase.

We propose a modified mechanism for the inhibition of [NiFe]hydrogenase ([NiFe]H(2)ase) by CO. We present a model study, using a NiRu H(2)ase mimic, that demonstrates that (i) CO completely inhibits the catalytic cycle of the model compound, (ii) CO prefers to coordinate to the Ru(II) center rather than taking an axial position on the Ni(II) center, and (iii) CO is unable to displace a hydrido ligand from the NiRu center. We combine these studies with a reevaluation of previous studies to propose that, under normal circumstances, CO inhibits [NiFe]H(2)ase by complexing to the Fe(II) center.

Concerto catalysis--harmonising [NiFe]hydrogenase and NiRu model catalysts.

This communication reports the successful merging of the chemical properties of a natural [NiFe]hydrogenase (Desulfovibrio vulgaris Miyazaki F) and our previously reported [NiRu] hydrogenase-mimic. The catalytic activity of both the natural enzyme and the mimic is almost identical, with the exception of working pH ranges, and this allows us to use them simultaneously in the same reaction flask. In such a manner, isotope exchange between D(2) and H(2)O could be conducted over an extended pH range (about 2-10) in one pot under mild conditions at ambient temperature and pressure.