Structure of WzzE Polysaccharide Co-polymeraseStructure of WzzE Polysaccharide Co-polymerase

Structural highlights

4wl1 is a 32 chain structure with sequence from Escherichia coli O157:H7. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:X-ray diffraction, Resolution 5.989Å
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

WZZE_ECO57

Publication Abstract from PubMed

Bacteria have evolved cellular control mechanisms to ensure proper length specification for surface-bound polysaccharides. Members of the Polysaccharide Co-Polymerase (PCP) family are central to this process. PCP-1 family members are anchored to the inner membrane through two transmembrane helices and contain a large periplasm-exposed domain. PCPs are known to form homooligomers but their exact stoichiometry is controversial in view of conflicting structural and biochemical data. Several prior investigations addressing this question indicated a nonameric, hexameric or tetrameric organization of several PCP-1 family members. In this work, we gathered additional evidence that E.coli WzzB and WzzE PCPs form octameric homo-oligomeric complexes. Detergent-solubilized PCPs were purified to homogeneity and subjected to blue native gel analysis, which indicated the presence of a predominant high-molecular product of over 500 kDa in mass. Molecular mass of WzzE and WzzB-detergent oligomers was estimated to be 550 kDA by size-exclusion coupled to multi-angle laser light scattering (SEC-MALLS). Oligomeric organization of purified WzzB and WzzE was further investigated by negative stain electron microscopy and by X-ray crystallography, respectively. Analysis of EM-derived molecular envelope of WzzB indicated that the full-length protein is composed of eight protomers. Crystal structure of LDAO-solubilized WzzE was solved to 6A resolution and revealed its octameric subunit stoichiometry. In summary, we identified a possible biological unit utilized for the glycan chain length determination by two PCP-1 family members. This provides an important step toward further unraveling of the mechanistic basis of chain length control of the O-antigen and the enterobacterial common antigen.

Quaternary structure of WzzB and WzzE polysaccharide co-polymerases.,Kalynych S, Cherney M, Bostina M, Rouiller I, Cygler M Protein Sci. 2014 Oct 11. doi: 10.1002/pro.2586. PMID:25307743[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

  1. Kalynych S, Cherney M, Bostina M, Rouiller I, Cygler M. Quaternary structure of WzzB and WzzE polysaccharide co-polymerases. Protein Sci. 2014 Oct 11. doi: 10.1002/pro.2586. PMID:25307743 doi:http://dx.doi.org/10.1002/pro.2586

4wl1, resolution 5.99Å

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