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Novel D-glutamate catabolic pathway in marine Proteobacteria and halophilic archaea

journal contribution
posted on 2023-05-21, 16:01 authored by Yu, Y, Wang, P, Cao, H-Y, Teng, Z-J, Zhu, Y, Wang, M, Andrew McMinnAndrew McMinn, Chen, Y, Xiang, H, Zhang, Y-Z, Chen, X-L, Zhang, Y-Q

D-glutamate (D-Glu) is an essential component of bacterial peptidoglycans, representing an important, yet overlooked, pool of organic matter in global oceans. However, little is known on D-Glu catabolism by marine microorganisms. Here, a novel catabolic pathway for D-Glu was identified using the marine bacterium Pseudoalteromonas sp. CF6-2 as the model. Two novel enzymes (DgcN, DgcA), together with a transcriptional regulator DgcR, are crucial for D-Glu catabolism in strain CF6-2. Genetic and biochemical data confirm that DgcN is a N-acetyltransferase which catalyzes the formation of N-acetyl-D-Glu from D-Glu. DgcA is a racemase that converts N-acetyl-D-Glu to N-acetyl-L-Glu, which is further hydrolyzed to L-Glu. DgcR positively regulates the transcription of dgcN and dgcA. Structural and biochemical analyses suggested that DgcN and its homologs, which use D-Glu as the acyl receptor, represent a new group of the general control non-repressible 5 (GCN5)-related N-acetyltransferases (GNAT) superfamily. DgcA and DgcN occur widely in marine bacteria (particularly Rhodobacterales) and halophilic archaea (Halobacteria) and are abundant in marine and hypersaline metagenome datasets. Thus, this study reveals a novel D-Glu catabolic pathway in ecologically important marine bacteria and halophilic archaea and helps better understand the catabolism and recycling of D-Glu in these ecosystems.


Publication title

The ISME Journal








Institute for Marine and Antarctic Studies


Nature Publishing Group

Place of publication

United Kingdom

Rights statement

© The Author(s), under exclusive licence to International Society for Microbial Ecology 2023

Repository Status

  • Restricted

Socio-economic Objectives

Coastal or estuarine biodiversity

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