RESUMO
Gordonia polyisoprenivorans 135 is a promising degrader of aromatic hydrocarbons. It can utilize phenanthrene, anthracene, benzoate, chlorobenzoates, and phenol. The genome of strain 135 was completely sequenced; it consists of a single 5,988,360-bp circular chromosome (GC content of 67.01%).
RESUMO
Microorganisms capable of decomposing hydrophobic substrates in cold climates are of considerable interest both in terms of studying adaptive reactions to low temperatures and in terms of their application in biotechnologies for cleaning up oil spills in a crude-oil polluted soil. The aim of this work was to investigate the genome of Rhodococcus opacus S8 and explore behavior traits of this strain grown in the presence of hexadecane. The genome size of strain S8 is 8.78 Mb, of which the chromosome size is 7.75 Mb. The S8 strain contains 2 circular plasmids of 135 kb and 105 kb and a linear plasmid with a size of 788 kb. The analysis of the genome revealed the presence of genes responsible for the degradation of alkanes and synthesis of biosurfactants. The peculiarities of morphology of microbial cells when interacting with a hydrophobic substrate were revealed. An adaptive mechanism responsible in the absence of oxygen for maintaining the process of degradation of hexadecane is discussed. The data obtained show that the strain S8 has great potential to be used in biotechnologies.
RESUMO
The strain Rhodococcus qingshengii VT6 is a promising degrader of persistent pollutants and a putative biosurfactant producer. The genome of the strain was sequenced completely. It consists of a 6,457,868-bp chromosome and 4 plasmids (pLP1, 501,672 bp; pLP2, 188,969 bp; pCP1, 100,387 bp; and pCP2, 132,858 bp).
RESUMO
Several peripheral metabolic pathways can be used by microorganisms to degrade toxic aromatic compounds that are known to pollute the environment. Hydroxyquinol (1,2,4-trihydroxybenzene) is one of the central intermediates in the degradative pathway of a large variety of aromatic compounds. The present review describes the microorganisms involved in the degradative pathway, the key enzymes involved in the formation and splitting of the aromatic ring of (chloro)hydroxyquinol as well as the central intermediates formed. An attempt was also made to provide some estimation for genetic basis of the hydroxyquinol pathway.
Assuntos
Bactérias/metabolismo , Biodegradação Ambiental , Hidroquinonas/metabolismo , Xenobióticos/metabolismo , Bactérias/enzimologia , Bactérias/genética , Enzimas/metabolismo , Hidrocarbonetos Aromáticos/metabolismo , Hidrocarbonetos Halogenados/metabolismoRESUMO
Hydroxyquinol 1,2-dioxygenase (1,2-HQD) catalyzes the ring cleavage of hydroxyquinol (1,2,4-trihydroxybenzene), a central intermediate in the degradation of aromatic compounds including a variety of particularly recalcitrant polychloro- and nitroaromatic pollutants. We report here the primary sequence determination and the analysis of the crystal structure of the 1,2-HQD from Nocardioides simplex 3E solved at 1.75 A resolution using the multiple wavelength anomalous dispersion of the two catalytic irons (1 Fe/293 amino acids). The catalytic Fe(III) coordination polyhedron composed by the side chains of Tyr164, Tyr197, His221, and His223 resembles that of the other known intradiol-cleaving dioxygenases, but several of the tertiary structure features are notably different. One of the most distinctive characteristics of the present structure is the extensive openings and consequent exposure to solvent of the upper part of the catalytic cavity arranged to favor the binding of hydroxyquinols but not catechols. A co-crystallized benzoate-like molecule is also found bound to the metal center forming a distinctive hydrogen bond network as observed previously also in 4-chlorocatechol 1,2-dioxygenase from Rhodococcus opacus 1CP. This is the first structure of an intradiol dioxygenase specialized in hydroxyquinol ring cleavage to be investigated in detail.
Assuntos
Actinomycetales/metabolismo , Dioxigenases/química , Algoritmos , Sequência de Aminoácidos , Sítios de Ligação , Catálise , Domínio Catalítico , Catecóis/química , Clonagem Molecular , Cristalografia por Raios X , Histidina/química , Ligação de Hidrogênio , Íons , Cinética , Metais/química , Modelos Químicos , Modelos Moleculares , Dados de Sequência Molecular , Reação em Cadeia da Polimerase , Conformação Proteica , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Homologia de Sequência de Aminoácidos , Especificidade por Substrato , Sulfatos/química , Temperatura , Tirosina/químicaRESUMO
In this paper we report the isolation and characterization of an anaerobic enrichment culture as well as of a Rhodococcus sp. strain 2 capable of degrading 3,4-dihaloanilines under nitrate reducing conditions. Using mass spectrometry several of the intermediates formed in the process of 3,4-dichloroaniline conversion were identified. Most interesting is the observation of reductive deamination and the formation of 1,2-dichlorobenzene as one of the intermediates. Using 19F NMR and fluorinated 3,4-dihaloaniline model substrates it was corroborated that reductive deamination of the anilines to give dihalobenzene intermediates represents a new initial step in the anaerobic microbial degradation of these halogenated anilines.