Selectivity in a barren landscape: the P450BioI–ACP complex

2010 ◽  
Vol 38 (4) ◽  
pp. 934-939 ◽  
Author(s):  
Max J. Cryle

The cytochromes P450 (P450s) are a superfamily of oxidative haemoproteins that are capable of catalysing a vast range of oxidative transformations, including the oxidation of unactivated alkanes, often with high stereo- and regio-selectivity. Fatty acid hydroxylation by P450s is widespread across both bacteria and higher organisms, with the sites of oxidation and specificity of oxidation varying from system to system. Several key examples are discussed in the present article, with the focus on P450BioI (CYP107H1), a biosynthetic P450 found in the biotin operon of Bacillus subtilis. The biosynthetic function of P450BioI is the formation of pimelic acid, a biotin precursor, via a multiple-step oxidative cleavage of long-chain fatty acids. P450BioI is a member of an important subgroup of P450s that accept their substrates not free in solution, but rather presented by a separate carrier protein. Structural characterization of the P450BioI–ACP (acyl-carrier protein) complex has recently been performed, which has revealed the basis for the oxidation of the centre of the fatty acid chain. The P450BioI–ACP structure is the first such P450–carrier protein complex to be characterized structurally, with important implications for other biosynthetically intriguing P450–carrier protein complexes.

2021 ◽  
Author(s):  
fangxiang hu ◽  
Weijie Cai ◽  
Junzhang Lin ◽  
Weidong Wang ◽  
Shuang Li

Abstract BackgroundSurfactin, a representative biosurfactant of popeptide mainly produced by Bacillus subtilis, consists of a cyclic heptapeptide linked to a β-hydroxy fatty acid chain. The functional activity of surfactin is closely related to the length and isomerism of the fatty acid chain. ResultsIn this study, the plant medium-chain acyl-carrier protein (ACP) thioesterase (BTE) from Umbellularia californica was overexpressed in a recombinant surfactin production strain based on B. subtilis 168. As a result, the surfactin yield after 24 h of cultivation improved by 23%, and the production rate increased from 0.112 to 0.177 g/L/h. The isoforms identified by RP-HPLC and GC-MS showed that the proportion of nC14-surfactin increased 6.4 times compared to the control strain. A comparison of further properties revealed that the product with more nC14-surfactin had higher surface activity and better performance in oil-washing. Finally, the product with more nC14-surfactin isoform had a higher hydrocarbon-emulsification index, and it increased the water-wettability of the oil-saturated silicate surface. ConclusionThe obtained results provide an original approach to modify the fatty acid chain of surfactin and further demonstrate the importance of the length and isomerism of the β-hydroxy fatty acid chain for the MEOR application of surfactin.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Woo Cheol Lee ◽  
Sungjae Choi ◽  
Ahjin Jang ◽  
Kkabi Son ◽  
Yangmee Kim

AbstractSome Gram-negative bacteria harbor lipids with aryl polyene (APE) moieties. Biosynthesis gene clusters (BGCs) for APE biosynthesis exhibit striking similarities with fatty acid synthase (FAS) genes. Despite their broad distribution among pathogenic and symbiotic bacteria, the detailed roles of the metabolic products of APE gene clusters are unclear. Here, we determined the crystal structures of the β-ketoacyl-acyl carrier protein (ACP) reductase ApeQ produced by an APE gene cluster from clinically isolated virulent Acinetobacter baumannii in two states (bound and unbound to NADPH). An in vitro visible absorption spectrum assay of the APE polyene moiety revealed that the β-ketoacyl-ACP reductase FabG from the A. baumannii FAS gene cluster cannot be substituted for ApeQ in APE biosynthesis. Comparison with the FabG structure exhibited distinct surface electrostatic potential profiles for ApeQ, suggesting a positively charged arginine patch as the cognate ACP-binding site. Binding modeling for the aryl group predicted that Leu185 (Phe183 in FabG) in ApeQ is responsible for 4-benzoyl moiety recognition. Isothermal titration and arginine patch mutagenesis experiments corroborated these results. These structure–function insights of a unique reductase in the APE BGC in comparison with FAS provide new directions for elucidating host–pathogen interaction mechanisms and novel antibiotics discovery.


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