The small RbcS-like domains of the β-carboxysome structural protein CcmM bind RubisCO at a site distinct from that binding the RbcS subunit.

ABSTRACT: Carboxysomes are compartments in bacterial cells that promote efficient carbon fixation by sequestering RubisCO and carbonic anhydrase within a protein shell that impedes CO₂ escape. The key to assembling this protein complex is CcmM, a multidomain protein whose C-terminal region is required for RubisCO recruitment. This CcmM region is built as a series of copies (generally 3-5) of a small domain, CcmM_S, joined by unstructured linkers. CcmM_S domains have weak, but significant, sequence identity to RubisCO's small subunit, RbcS, suggesting that CcmM binds RubisCO by displacing RbcS. We report here the 1.35-Å structure of the first Thermosynechococcus elongatus CcmM_S domain, revealing that it adopts a compact, well-defined structure that res

SUBMITTER: Ryan P 

PROVIDER: S-EPMC6393606 | biostudies-literature | 2019 Feb

REPOSITORIES: biostudies-literature