Campus Units

Biochemistry, Biophysics and Molecular Biology, Roy J. Carver Department of

Document Type

Article

Publication Version

Published Version

Publication Date

10-2018

Journal or Book Title

Molecules

Volume

23

Issue

10

First Page

2546

DOI

10.3390/molecules23102546

Abstract

Isoprenyl chains are found in many important metabolites. These are derived from precursors of the appropriate length produced by isoprenyl diphosphate synthases (IDSs). The human pathogen Mycobacterium tuberculosis makes various isoprenoids/terpenoids, with important roles in their biosynthesis played by two closely related IDSs, encoded by grcC1 (Rv0562) and grcC2 (Rv0989c), with Rv0989c generating the 10-carbon precursor (E)-geranyl diphosphate (GPP), and Rv0562 the 20-carbon precursor (E,E,E)-geranylgeranyl diphosphate (GGPP). Intriguingly, while Rv0562 contains the prototypical trans-IDS first and second aspartate-rich (DDxxD) motifs (FARM and SARM, respectively), Rv0989c uniquely contains arginine in place of the second Asp in the FARM and first Asp in the SARM. Here site-directed mutagenesis of the corresponding residues in both Rv0562 and Rv0989c reveals that these play a role in determination of product chain length. Specifically, substitution of Asp for the Arg in the FARM and SARM of Rv0989c leads to increased production of the longer 15-carbon farnesyl diphosphate (FPP), while substitution of Arg for the corresponding Asp in Rv0562 leads to increased release of shorter products, both FPP and GPP. Accordingly, while the primary role of the FARM and SARM is known to be chelation of the divalent magnesium ion co-factors that assist substrate binding and catalysis, the Arg substitutions found in Rv0989c seem to provide a novel means by which product chain length is moderated, at least in these M. tuberculosis IDSs.

Comments

This article is published as Nagel, Raimund, Jill Thomas, Faith Adekunle, Francis Mann, and Reuben Peters. "Arginine in the FARM and SARM: a role in chain-length determination for arginine in the aspartate-rich motifs of Isoprenyl diphosphate synthases from Mycobacterium tuberculosis." Molecules 23, no. 10 (2018): 2546. doi: 10.3390/molecules23102546.

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Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

Copyright Owner

The Authors

Language

en

File Format

application/pdf

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