Crystal structure of a novel xylose isomerase from Streptomyces sp. F-1 revealed the presence of unique features that differ from conventional classes

• Autor(a) principal: Miyamoto, Renan Yuji
• Data de Publicação: 2020
• Outros Autores: Sousa, Amanda Silva de, Vieira, Plinio Salmazo, Melo, Ricardo Rodrigues de, Scarpassa, Josiane Aniele [UNESP], Inacio Ramos, Carlos Henrique, Murakami, Mario Tyago, Ruller, Roberto, Zanphorlin, Leticia Maria
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://dx.doi.org/10.1016/j.bbagen.2020.129549; http://hdl.handle.net/11449/195264
• topic: Xylose isomerase; Crystal structure; Enzyme kinetics; Structure-function relationship; Hemicellulosic fraction; Biofuels

Background: Enzymatic isomerization is a promising strategy to solve the problem of xylose fermentation and, consequently, to leverage the production of advanced biofuels and biochemicals. In a previous work, our research group discovered a new strain of Streptomyces with great biotechnological potential due to its ability to produce a broad arsenal of enzymes related to lignocellulose degradation. Methods: We applied a multidisciplinary approach involving enzyme kinetics, biophysical methods, small angle X-ray scattering and X-ray crystallography to investigate two novel xylose isomerases, XylAlF1 and XylA2F1, from this strain. Results: We showed that while XylAlF1 prefers to act at lower temperatures and relatively lower pH, XylA2F1 is extremely stable at higher temperatures and presents a higher turnover number. Structural analysis revealed that XylA1F1 exhibits unique properties in the active site not observed in classical XylAs from classes I and II nor in its ortholog XylA2F1. It encompasses the natural substitutions, M86A and T93K, that create an extra room for substrate accommodation and narrow the active-site entrance, respectively. Such modifications may contribute to the functional differentiation of these enzymes. Conclusions: We have characterized two novel xylose isomerases that display distinct functional behavior and harbor unprecedented amino-acid substitutions in the catalytic interface. General significance: Our findings contribute to a better understanding of the functional and structural aspects of xylose isomerases, which might be instrumental for the valorization of the hemicellulosic fraction of vegetal biomass.