The enzymes for the degradation of short- and medium-chain length n-alkanes are rather well characterized, although there is a paucity of structural data. Availability of data and materials Not applicable. Similarly, CYP genes were found in all the sequenced genomes of Bradyrhizobium, Rhodopseudomonas, Caulobacter and Novosphingobium, also indicating their potential core roles in these genera Fig.
Furthermore, of all the 15 complete Actinobacteria genomes, predicted GIs containing CYP genes were found in eight genomes, and plasmids containing CYP genes were found in three genomes. Only about TY-6 and Nocardioides sp. HXN has been purified and shown to hydroxylate C6—C11 n-alkanes to 1-alkanols with high affinity and regioselectivity Funhoff et al.
These glycolipids are virulence determinants associated with M. Figure 4: Taxonomic distribution of alkane hydroxylases in freshwater, marine and terrestrial habitats. Although the functions and evolution of AH genes and the mechanism of how organisms and genes are selected in different habitats need to be further researched, our work provides an overall profile of the alkB and CYP gene distributions in microbes and environments which can help to understand the gene and microbial functions toward alkane degradation in different environments. Availability of data and materials Not applicable.
Overexpressed enzymes are shown by blue color; enzymes whose genes have been deleted from the chromosome are shown by red color. This growth phase-depended regulation of CFA synthesis is caused by a RpoS-dependent promoter, which is activated only when cells enter stationary phase. Only two freshwater sequences were related to alkB sequences from Actinobacteria in Cluster I. They can be produced from fatty acid metabolites of plants, insects, and microorganisms. It is common for catabolic genes to undergo genetic rearrangements, such as insertions, deletions, duplications and inversions, which is attributable to the presence of elements that possess the ability to mobilise the catabolic genes
The rapid evolutionary events like HGT, gene duplication, and gene fusion likely contributed to the diversity of both the alkB and CYP genes. Knothe G, Dunn RO. Curr Opin Biotechnol. However, the distribution of these two genes was uneven: However, some findings indicate that, in several microorganisms, C20—C50 n-alkanes are probably oxidized by enzymes yet to be identified. Although 2-propanol can be oxidized by any of these three secondary ADHs, which are all expressed in propane-grown cells, ADH1 seemed to play the major role under the conditions in the latter report.
In general, bacterial Ps usually need ferredoxin and ferredoxin reductase for electron transfer. An in vitro study of the E. S9 and S The DNA binding activity of BkdR can be further enhanced by branched-chain amino acids as demonstrated in Pseudomonas putida, [ 55 ].
Overexpressed enzymes are shown by blue color; enzymes whose genes have been deleted from the chromosome are shown by red color. However, several bacterial strains can degrade simple branched-chain alkanes such as isooctane Solano-Serena et al. Moreover, no alkB or CYP homologous genes from Firmicutes were found in all the three metagenomic datasets. From the clustering in the phylogenetic tree, the potentially same ancient ancestor of CYP genes could be found from Alcanivorax, Marinobacter, Acinetobacter, and Actinobacteria Fig. Sequences of Cluster III were all from Gammaproteobacteria, including all the sequences from Acinetobacter, and sequences from some Marinobacter and Psychrobacter species.
However, their deduced proteins contained all the residues that are conserved in alkane hydroxylases. Except for the genomes of Pelagibaca bermudensis HTCC, Octadecabacter arcticus and Rhodobacter capsulatus SB , genomes in group 2 always had more than two alkB genes: one was in group 2 and the others in group 1. References 1.