Crystal structure of the TreS:Pep2 complex, initiating α-glucan synthesis in the GlgE pathway of mycobacteria

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dc.contributor.authorKermani, Ali A.
dc.contributor.authorRoy, Rana
dc.contributor.authorGopalasingam, Chai
dc.contributor.authorKocurek, Klaudia I.
dc.contributor.authorPatel, Trushar R.
dc.contributor.authorAlderwick, Luke J.
dc.contributor.authorBesra, Gurdyal S.
dc.contributor.authorFütterer, Klaus
dc.date.accessioned2024-07-11T19:02:46Z
dc.date.available2024-07-11T19:02:46Z
dc.date.issued2019
dc.descriptionOpen access article. Creative Commons Attribution 4.0 International license (CC BY 4.0) applies
dc.description.abstractA growing body of evidence implicates the mycobacterial capsule, the outermost layer of the mycobacterial cell envelope, in modulation of the host immune response and virulence of mycobacteria. Mycobacteria synthesize the dominant capsule component, α(1→4)-linked glucan, via three interconnected and potentially redundant metabolic pathways. Here, we report the crystal structure of the Mycobacterium smegmatis TreS:Pep2 complex, containing trehalose synthase (TreS) and maltokinase (Pep2), which converts trehalose to maltose 1-phosphate as part of the TreS:Pep2–GlgE pathway. The structure, at 3.6 Å resolution, revealed that a diamond-shaped TreS tetramer forms the core of the complex and that pairs of Pep2 monomers bind to opposite apices of the tetramer in a 4 + 4 configuration. However, for the M. smegmatis orthologues, results from isothermal titration calorimetry and analytical ultracentrifugation experiments indicated that the prevalent stoichiometry in solution is 4 TreS + 2 Pep2 protomers. The observed discrepancy between the crystallized complex and the behavior in the solution state may be explained by the relatively weak affinity of Pep2 for TreS (Kd 3.5 μm at mildly acidic pH) and crystal packing favoring the 4 + 4 complex. Proximity of the ATP-binding site in Pep2 to the complex interface provides a rational basis for rate enhancement of Pep2 upon binding to TreS, but the complex structure appears to rule out substrate channeling between the active sites of TreS and Pep2. Our findings provide a structural model for the trehalose synthase:maltokinase complex in M. smegmatis that offers critical insights into capsule assembly.
dc.identifier.citationKermani, A. A., Roy, R., Gopalasingam, C., Kocurek, K. I., Patel, T. R., Alderwick, L. J., Besra, G. S., & Fütterer, K. (2019). Crystal structure of the TreS:Pep2 complex, initiating α-glucan synthesis in the GlgE pathway of mycobacteria. Journal of Biological Chemistry, 294(18), 7348-7359. https://doi.org/10.1074/jbc.RA118.004297
dc.identifier.urihttps://hdl.handle.net/10133/6814
dc.language.isoen
dc.publisherAmerican Society for Biochemistry and Molecular Biology
dc.publisher.departmentDepartment of Chemistry and Biochemistry
dc.publisher.facultyArts and Science
dc.publisher.institutionUniversity of Michigan
dc.publisher.institutionUniversity of Lethbridge
dc.publisher.urlhttps://doi.org/10.1074/jbc.RA118.004297
dc.subjectMycobacteria
dc.subjectAnalytical ultracentrifugation
dc.subjectX-ray crystallography
dc.subjectTrehalose
dc.subjectEnzyme catalysis
dc.subjectProtein complex
dc.subjectPathogenesis
dc.subjectα-glucan
dc.subjectCapsule
dc.subjectImmune evasion
dc.subjectMaltose kinase
dc.subjectTrehalose synthase
dc.titleCrystal structure of the TreS:Pep2 complex, initiating α-glucan synthesis in the GlgE pathway of mycobacteria
dc.typeArticle
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