CNPEM study reveals novel enzyme mechanism with potential for biofuels and biotechnology

The new discovery will aid in the development of more efficient and sustainable technologies for bioenergy generation

A study led by researchers from the Brazilian Center for Research in Energy and Materials (CNPEM), located in Campinas (SP), has identified a novel molecular mechanism that explains how enzymes degrade beta-glucans, a class of carbohydrates found in fungi, algae, and plants, with great relevance for industrial and energy applications. The research involved approximately 18 collaborators from the LNBR (Brazilian Biorenewables National Laboratory) and the LNLS (Brazilian Synchrotron Light Laboratory), both part of CNPEM, in addition to external researchers from Unicamp and universities in Spain and Canada.

Published in the scientific journal Nature Communications, the work describes, for the first time, a process called processive catalysis applied to the breakdown of these compounds. In this mechanism, the enzyme acts continuously on the same molecular chain, without detaching itself after each stage of the reaction, which makes the process more efficient.

According to researcher Mariana Morais, one of the study coordinators, the work utilized various techniques and equipment at CNPEM, including directed mutagenesis techniques and kinetic analyses. The research also included high-resolution X-ray crystallography experiments conducted at Sirius, CNPEM’s particle accelerator, as well as computer simulations carried out on the Santos Dumont supercomputer, at the National Laboratory for Scientific Computing (LNCC).

“This integration allowed for the observation, at the atomic level, of all stages of the enzymatic process, from substrate recognition to product release and the restart of the catalytic cycle”, says Morais.

Read more on the CNPEM website

Image: Representation of the enzyme forming a catalytic tunnel that enables interaction with the beta-glucan chain and its continuous processing

New studies towards lignin valorisation

A little known, yet ubiquitous polymer

In work recently published in PNAS an international team of researchers characterised an important degradation step, allowing the breakage of lignin that leads to the production of individual components, which can be further harvested. To do so, they utilise several Diamond Light Source instruments:  the I23, I03 and B21 beamlines.

Compared to animals, plants don’t have a bony skeleton. They rely on rigid cell walls that separate each plant cell. These cell walls are composed of cellulose, pectin and lignin, making these molecules among the most abundant on earth. Lignin is a hydrophobic compound and plays a crucial role in vascular tissue, making them impermeable and allowing the transport of water in the plant efficiently. Lignin is a huge and complex molecule composed of different precursors called monolignols. The composition of lignin varies among plants.

From an industrial perspective, lignin is well known in the paper industry because it represents a third of the mass of the paper precursor. Lignin is a coloured component that yellows in the air and needs to be removed to have white paper. Currently there is only limited use for lignin and it is burned as low value fuel in these industries. New research and development have improved the transformation of lignin into value added components (biofuels, chemical compounds…) but research is still needed to improve the degradation process of lignin. A way to harvest these components is through enzymatic degradation. In work recently published in PNAS an international team of researchers characterised an important degradation step, allowing the breakage of lignin that leads to the production of individual components, which can be further harvested. To do so, they utilise several Diamond Light Source instruments:  the I23, I03 and B21 beamlines.

Read more on the Diamond website

Image: Structural architecture of LdpA and substrate interactions. (A) Superposition of SpLdpA (magenta) with NaLdpA (teal). (B) Side view of the SpLdpA trimer. Two protein chains are shown as surfaces (yellow and green) and one protein chain is shown in cartoon mode (red) with bound substrate erythro-DGPD (light blue). (C) Top view of the SpLdpA trimer. (D) Pseudo-stereoscopic view of the interaction of SpLdpA with the erythro-DGPD enantiomers (αS, βR) (Left) and (αR, βS) (Right). When viewed in stereo, alternating eye switching results in an optimal impression of the binding modes of the two diastereomer substrates. (E) Omit electron density map for the (αS, βR)- and (αR, βS)-erythro-DGPD enantiomers bound to SpLdpA at 2.5 σ level. (see Diamond news piece for complete image)