Structure of the type II thioesterase BorB from the borrelidin biosynthetic clusterStructure of the type II thioesterase BorB from the borrelidin biosynthetic cluster

Structural highlights

6vap is a 2 chain structure with sequence from Streptomyces sp. WAC02707. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:X-ray diffraction, Resolution 1.93Å
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

A0A454WD44_9ACTN

Publication Abstract from PubMed

alpha/beta hydrolases make up a large and diverse protein superfamily. In natural product biosynthesis, cis-acting thioesterase alpha/beta hydrolases can terminate biosynthetic assembly lines and release products by hydrolyzing or cyclizing the biosynthetic intermediate. Thioesterases can also act in trans, removing aberrant intermediates and restarting stalled biosynthesis. Knockout of this "editing" function leads to reduced product titers. The borrelidin biosynthetic gene cluster from Streptomyces parvulus Tu4055 contains a hitherto uncharacterized stand-alone thioesterase, borB. In this work, we demonstrate that purified BorB cleaves acyl substrates with a preference for propionate, which supports the hypothesis that it is also an editing thioesterase. The crystal structure of BorB shows a wedgelike hydrophobic substrate binding crevice that limits substrate length. To investigate the structure-function relationship, we made chimeric BorB variants using loop regions from characterized homologues with different specificities. BorB chimeras slightly reduced activity, arguing that the modified region is a not major determinant of substrate preference. The structure-function relationships described here contribute to the process of elimination for understanding thioesterase specificity and, ultimately, engineering and applying trans-acting thioesterases in biosynthetic assembly lines.

Structure and Function of BorB, the Type II Thioesterase from the Borrelidin Biosynthetic Gene Cluster.,Curran SC, Pereira JH, Baluyot MJ, Lake J, Puetz H, Rosenburg DJ, Adams P, Keasling JD Biochemistry. 2020 Apr 28;59(16):1630-1639. doi: 10.1021/acs.biochem.0c00126., Epub 2020 Apr 13. PMID:32250597[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

See Also

References

  1. Curran SC, Pereira JH, Baluyot MJ, Lake J, Puetz H, Rosenburg DJ, Adams P, Keasling JD. Structure and Function of BorB, the Type II Thioesterase from the Borrelidin Biosynthetic Gene Cluster. Biochemistry. 2020 Apr 28;59(16):1630-1639. doi: 10.1021/acs.biochem.0c00126., Epub 2020 Apr 13. PMID:32250597 doi:http://dx.doi.org/10.1021/acs.biochem.0c00126

6vap, resolution 1.93Å

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