Title: Peroxidase evolution in white-rot fungi follows wood lignin evolution in plants

Abstract

A comparison of sequenced Agaricomycotina genomes suggests that efficient degradation of wood lignin was associated with the appearance of secreted peroxidases with a solvent-exposed catalytic tryptophan. This hypothesis is experimentally demonstrated here by resurrecting ancestral fungal peroxidases, after sequence reconstruction from genomes of extant white-rot Polyporales, and evaluating their oxidative attack on the lignin polymer by state-of-the-art analytical techniques. Rapid stopped-flow estimation of the transient-state constants for the 2 successive one-electron transfers from lignin to the peroxide-activated enzyme (k_2appandk_3app) showed a progressive increase during peroxidase evolution (up to 50-fold higher values for the rate-limitingk_3app). The above agreed with 2-dimensional NMR analyses during steady-state treatments of hardwood lignin, showing that its degradation (estimated from the normalized aromatic signals of lignin units compared with a control) and syringyl-to-guaiacyl ratio increased with the enzyme evolutionary distance from the first peroxidase ancestor. More interestingly, the stopped-flow estimations of electron transfer rates also showed how the most recent peroxidase ancestors that already incorporated the exposed tryptophan into their molecular structure (as well as the extant lignin peroxidase) were comparatively more efficient at oxidizing hardwood (angiosperm) lignin, while the most ancestral “tryptophanless” enzymes were more efficient at abstracting electrons from softwood (conifer) lignin. A time calibrationmore » of the ancestry of Polyporales peroxidases localized the appearance of the first peroxidase with a solvent-exposed catalytic tryptophan to 194 ± 70 Mya, coincident with the diversification of angiosperm plants characterized by the appearance of dimethoxylated syringyl lignin units.« less

Authors:

Ayuso-Fernández, Iván  ^[1];

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• Search DOE PAGES for ORCID "0000-0001-8503-2615"
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Rencoret, Jorge  ^[2];

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• Search DOE PAGES for ORCID "0000-0003-2728-7331"
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Gutiérrez, Ana ^[2]; Ruiz-Dueñas, Francisco Javier  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-9837-5665"
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Martínez, Angel T.  ^[1]

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• Search DOE PAGES for ORCID "0000-0002-1584-2863"
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+ Show Author Affiliations

1. Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, E-28040 Madrid, Spain,
2. Instituto de Recursos Naturales y Agrobiología de Sevilla, Consejo Superior de Investigaciones Científicas E-41012 Seville, Spain

Publication Date:

2019-08-19

Research Org.:

Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC)

OSTI Identifier:

1564415

Alternate Identifier(s):

OSTI ID: 1625038

Grant/Contract Number:  

AC02-05CH11231

Resource Type:

Published Article

Journal Name:

Proceedings of the National Academy of Sciences of the United States of America

Additional Journal Information:

Journal Name: Proceedings of the National Academy of Sciences of the United States of America Journal Volume: 116 Journal Issue: 36; Journal ID: ISSN 0027-8424

Publisher:

Proceedings of the National Academy of Sciences

Country of Publication:

United States

Language:

English

Subject:

Science & Technology - Other Topics