Structural highlights
Function
RBL1_CERSP RuBisCO catalyzes two reactions: the carboxylation of D-ribulose 1,5-bisphosphate, the primary event in carbon dioxide fixation, as well as the oxidative fragmentation of the pentose substrate. Both reactions occur simultaneously and in competition at the same active site.[HAMAP-Rule:MF_01338][1]
Publication Abstract from PubMed
How AAA+ chaperones conformationally remodel specific target proteins in an ATP-dependent manner is not well understood. Here, we investigated the mechanism of the AAA+ protein Rubisco activase (Rca) in metabolic repair of the photosynthetic enzyme Rubisco, a complex of eight large (RbcL) and eight small (RbcS) subunits containing eight catalytic sites. Rubisco is prone to inhibition by tight-binding sugar phosphates, whose removal is catalyzed by Rca. We engineered a stable Rca hexamer ring and analyzed its functional interaction with Rubisco. Hydrogen/deuterium exchange and chemical crosslinking showed that Rca structurally destabilizes elements of the Rubisco active site with remarkable selectivity. Cryo-electron microscopy revealed that Rca docks onto Rubisco over one active site at a time, positioning the C-terminal strand of RbcL, which stabilizes the catalytic center, for access to the Rca hexamer pore. The pulling force of Rca is fine-tuned to avoid global destabilization and allow for precise enzyme repair.
Mechanism of Enzyme Repair by the AAA+ Chaperone Rubisco Activase.,Bhat JY, Milicic G, Thieulin-Pardo G, Bracher A, Maxwell A, Ciniawsky S, Mueller-Cajar O, Engen JR, Hartl FU, Wendler P, Hayer-Hartl M Mol Cell. 2017 Jul 20. pii: S1097-2765(17)30498-7. doi:, 10.1016/j.molcel.2017.07.004. PMID:28803776[2]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Horken KM, Tabita FR. Closely related form I ribulose bisphosphate carboxylase/oxygenase molecules that possess different CO2/O2 substrate specificities. Arch Biochem Biophys. 1999 Jan 15;361(2):183-94. PMID:9882445 doi:http://dx.doi.org/S0003-9861(98)90979-1
- ↑ Bhat JY, Milicic G, Thieulin-Pardo G, Bracher A, Maxwell A, Ciniawsky S, Mueller-Cajar O, Engen JR, Hartl FU, Wendler P, Hayer-Hartl M. Mechanism of Enzyme Repair by the AAA+ Chaperone Rubisco Activase. Mol Cell. 2017 Jul 20. pii: S1097-2765(17)30498-7. doi:, 10.1016/j.molcel.2017.07.004. PMID:28803776 doi:http://dx.doi.org/10.1016/j.molcel.2017.07.004
