Campus Units

Biochemistry, Biophysics and Molecular Biology, Roy J. Carver Department of, Center for Biorenewable Chemicals, Center for Metabolic Biology

Document Type

Article

Publication Version

Published Version

Publication Date

1-2021

Journal or Book Title

Frontiers in Molecular Biosciences

Volume

7

First Page

615614

DOI

10.3389/fmolb.2020.615614

Abstract

Acyl-CoA carboxylases (AcCCase) are biotin-dependent enzymes that are capable of carboxylating more than one short chain acyl-CoA substrate. We have conducted structural and kinetic analyses of such an AcCCase from Thermobifida fusca YX, which exhibits promiscuity in carboxylating acetyl-CoA, propionyl-CoA, and butyryl-CoA. The enzyme consists of two catalytic subunits (TfAcCCA and TfAcCCB) and a non-catalytic subunit, TfAcCCE, and is organized in quaternary structure with a A6B6E6 stoichiometry. Moreover, this holoenzyme structure appears to be primarily assembled from two A3 and a B6E6 subcomplexes. The role of the TfAcCCE subunit is to facilitate the assembly of the holoenzyme complex, and thereby activate catalysis. Based on prior studies of an AcCCase from Streptomyces coelicolor, we explored whether a conserved Asp residue in the TfAcCCB subunit may have a role in determining the substrate selectivity of these types of enzymes. Mutating this D427 residue resulted in alterations in the substrate specificity of the TfAcCCase, increasing proficiency for carboxylating acetyl-CoA, while decreasing carboxylation proficiency with propionyl-CoA and butyryl-CoA. Collectively these results suggest that residue D427 of AcCCB subunits is an important, but not sole determinant of the substrate specificity of AcCCase enzymes.

Comments

This article is published as Shivaiah K-K, Upton B and Nikolau BJ (2021) Kinetic, Structural, and Mutational Analysis of Acyl-CoA Carboxylase From Thermobifida fusca YX. Front. Mol. Biosci. 7:615614. doi:10.3389/fmolb.2020.615614.

Creative Commons License

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

Copyright Owner

Shivaiah, Upton and Nikolau

Language

en

File Format

application/pdf

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