PXD058227

PXD058227 is an original dataset announced via ProteomeXchange.

Title	Identification of EcpK, a bacterial tyrosine pseudokinase important for exopolysaccharide biosynthesis in Myxococcus xanthus
Description	Bacteria secrete chemically diverse polysaccharides that function in many physiological processes and are widely used in industrial applications. In the ubiquitous Wzx/Wzy-dependent pathway for polysaccharide biosynthesis in Gram-negative bacteria, a polysaccharide co-polymerase (PCP) functions at the nexus between repeat-unit polymerization in the periplasm and polysaccharide translocation across the outer membrane by stimulating both processes. These PCPs are integral inner membrane proteins with extended periplasmic domains, and functionally depend on alternating between different oligomeric states. The oligomeric state, in turn, is determined by a cognate cytoplasmic bacterial Tyr kinase (BYK), which is either part of the PCP or a stand-alone protein, together with a Tyr phosphatase. Jointly, the BYK/phosphatase pair enables Tyr phosphorylation/dephosphorylation cycles, thereby facilitating the alternation between PCP oligomeric states. Interestingly, non-canonical BYK proteins, which lack key catalytic residues and/or the phosphorylated Tyr residues, have been described. In Myxococcus xanthus, the secreted polysaccharide EPS is synthesized and secreted via the Wzx/Wzy-dependent EPS pathway in which EpsV serves as the PCP. Here, we confirm that EpsV lacks the BYK domain. Using phylogenomics, experiments and computational structural biology, we identify EcpK as important for EPS biosynthesis and show that it structurally resembles canonical BYKs but lacks residues important for catalysis and Tyr phosphorylation. Using proteomic analyses, two-hybrid assays and structural modeling, we demonstrate that EcpK directly interacts with EpsV. Based on these findings, we suggest that EcpK functions as a scaffold and by direct protein-protein interactions, rather than by Tyr phosphorylation, facilitates EpsV activity. EcpK and EpsV orthologs are present in other bacteria, suggesting a broad conservation of this mechanism.
HostingRepository	PRIDE
AnnounceDate	2025-03-05
AnnouncementXML	Submission_2025-03-05_02:14:02.550.xml
DigitalObjectIdentifier
ReviewLevel	Peer-reviewed dataset
DatasetOrigin	Original dataset
RepositorySupport	Unsupported dataset by repository
PrimarySubmitter	Timo Glatter
SpeciesList	scientific name: Myxococcus xanthus; NCBI TaxID: 34;
ModificationList	No PTMs are included in the dataset
Instrument	Orbitrap Exploris 480

Revision	Datetime	Status	ChangeLog Entry
0	2024-11-25 04:14:33	ID requested
⏵ 1	2025-03-05 02:14:02	announced

Dataset with its publication pending

submitter keyword: exopolysaccharide biosynthesis,Myxococcus xanthus

Timo Glatter
contact affiliation	Max Planck Institute for Terrestrial Microbiology Karl-von-Frisch Str. 10 35043 Marburg Germany
contact email	timo.glatter@mpi-marburg.mpg.de
lab head
Timo Glatter
contact affiliation	Max Planck Institute for Terrestrial Microbiology Marburg
contact email	timo.glatter@mpi-marburg.mpg.de
dataset submitter

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PRIDE project URI

• PRIDE
  1. PXD058227
     1. Label: PRIDE project
     2. Name: Identification of EcpK, a bacterial tyrosine pseudokinase important for exopolysaccharide biosynthesis in Myxococcus xanthus