8TRX

Crystal structure of a CE15 glucuronoyl esterase from Piromyces rhizinflatus

Summary for 8TRX

• Entry DOI: 10.2210/pdb8trx/pdb
• Descriptor: CE15 glucuronoyl esterase (2 entities in total)
• Functional Keywords: carbohydrate, esterase, glucuronyl esterase, rumen, hydrolase
• Biological source: Piromyces rhizinflatus
• Total number of polymer chains: 2
• Total formula weight: 92211.12

Authors

Gruninger, R.J.,Jones, D.R. (deposition date: 2023-08-10, release date: 2024-08-28, Last modification date: 2024-10-09)

Primary citation

Gruninger, R.J.,Kevorkova, M.,Low, K.E.,Jones, D.R.,Worrall, L.,McAllister, T.A.,Abbott, D.W.
Structural, Biochemical, and Phylogenetic Analysis of Bacterial and Fungal Carbohydrate Esterase Family 15 Glucuronoyl Esterases in the Rumen.
Protein J., 43:910-922, 2024

PubMed Abstract: Glucuronoyl esterases (GEs) are carbohydrate active enzymes in carbohydrate esterase family 15 which are involved in the hydrolysis of lignin-carbohydrate complexes. They are encoded by a wide range of aerobic and anaerobic fungi and bacteria inhabiting diverse environments. The rumen microbiome is a complex microbial community with a wide array of enzymes that specialize in deconstructing plant cell wall carbohydrates. Enzymes from the rumen tend to show low similarity to homologues found in other environments, making the rumen microbiome a promising source for the discovery of novel enzymes. Using a combination of phylogenetic and structural analysis, we investigated the structure-function relationship of GEs from the rumen bacteria Fibrobacter succinogenes and Ruminococcus flavefaciens, and from the rumen fungus, Piromyces rhizinflata. All adopt a canonical α/β hydrolase fold and possess a structurally conserved Ser-His-Glu/Asp catalytic triad. Structural variations in the enzymes are localized to loops surrounding the active site. Analysis of the active site structures in these enzymes emphasized the importance of structural plasticity in GEs with non-canonical active site conformations. We hypothesize that interkingdom HGT events may have contributed to the diversity of GEs in the rumen, and this is demonstrated by the phylogenetic and structural similarity observed between rumen bacterial and fungal GEs. This study advances our understanding of the structure-function relationship in glucuronoyl esterases and illuminates the evolutionary dynamics that contribute to enzyme diversity in the rumen microbiome.

PubMed: 39153129
DOI: 10.1007/s10930-024-10221-0

Experimental method

X-RAY DIFFRACTION (2.54 Å)