Sulfate-compatible density marks an intratrimeric junction in the Escherichia coli dihydrolipoamide succinyltransferase catalytic domain

Lim, B.; Kim, E.; Byun, J.; Kim, M.; Kim, H.J.

doi:10.1107/S2053230X2600909X

Figure 1
Structural organization of the EcDSCD F432 assembly and sulfate-compatible density at the intratrimeric junction. (a) Surface representation of the symmetry-generated EcDSCD trimer, showing the interlocked arrangement of the three protomers. A symmetry-expanded view illustrates how eight trimers assemble into the 24-mer particle. (b) Close-up views of the symmetry-related intratrimeric interface. Representative interprotomer contacts show that the trimer interface is supported by complementary packing together with ionic interaction networks and hydrogen bonds. The boxed region in (a) is enlarged in (b). (c) Symmetry-expanded EcDSCD 24-mer assembly within the crystallographic unit cell, showing sulfate-compatible density near the Lys196-centered threefold intratrimeric junction. The 2F_o − F_c electron-density map is shown as a blue mesh contoured at 1.0σ, and the positive F_o − F_c difference map is shown as a green mesh contoured at 3.0σ. The sulfate ion was not modeled because symmetry-related copies would overlap at this position.

STRUCTURAL BIOLOGY
COMMUNICATIONS

ISSN: 2053-230X

Volume 82| Part 10| October 2026|

https://doi.org/10.1107/S2053230X2600909X

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