Molecular basis for metabolite channeling in a ring opening enzyme of the phenylacetate degradation pathway.
Title | Molecular basis for metabolite channeling in a ring opening enzyme of the phenylacetate degradation pathway. |
Publication Type | Journal Article |
Year of Publication | 2019 |
Authors | Sathyanarayanan N, Cannone G, Gakhar L, Katagihallimath N, Sowdhamini R, Ramaswamy S, Vinothkumar KR |
Journal | Nat Commun |
Volume | 10 |
Issue | 1 |
Pagination | 4127 |
Date Published | 2019 Sep 11 |
ISSN | 2041-1723 |
Abstract | Substrate channeling is a mechanism for the internal transfer of hydrophobic, unstable or toxic intermediates from the active site of one enzyme to another. Such transfer has previously been described to be mediated by a hydrophobic tunnel, the use of electrostatic highways or pivoting and by conformational changes. The enzyme PaaZ is used by many bacteria to degrade environmental pollutants. PaaZ is a bifunctional enzyme that catalyzes the ring opening of oxepin-CoA and converts it to 3-oxo-5,6-dehydrosuberyl-CoA. Here we report the structures of PaaZ determined by electron cryomicroscopy with and without bound ligands. The structures reveal that three domain-swapped dimers of the enzyme form a trilobed structure. A combination of small-angle X-ray scattering (SAXS), computational studies, mutagenesis and microbial growth experiments suggests that the key intermediate is transferred from one active site to the other by a mechanism of electrostatic pivoting of the CoA moiety, mediated by a set of conserved positively charged residues. |
DOI | 10.1038/s41467-019-11931-1 |
Alternate Journal | Nat Commun |
PubMed ID | 31511507 |
PubMed Central ID | PMC6739347 |