6HAS

Crystal Structure of the small subunit-like domain of Rubisco activase from Nostoc sp. (strain PCC 7120)

Summary for 6HAS

• Entry DOI: 10.2210/pdb6has/pdb
• Descriptor: Ribulose bisphosphate carboxylase/oxygenase activase, NICKEL (II) ION (3 entities in total)
• Functional Keywords: alpha-beta structure, rubisco, chaperone
• Biological source: Nostoc sp. (strain PCC 7120 / SAG 25.82 / UTEX 2576)
• Total number of polymer chains: 2
• Total formula weight: 20591.79

Authors

Popilka, L.,Bracher, A. (deposition date: 2018-08-08, release date: 2020-01-15, Last modification date: 2024-11-06)

Primary citation

Flecken, M.,Wang, H.,Popilka, L.,Hartl, F.U.,Bracher, A.,Hayer-Hartl, M.
Dual Functions of a Rubisco Activase in Metabolic Repair and Recruitment to Carboxysomes.
Cell, 183:457-473.e20, 2020

PubMed Abstract: Rubisco, the key enzyme of CO fixation in photosynthesis, is prone to inactivation by inhibitory sugar phosphates. Inhibited Rubisco undergoes conformational repair by the hexameric AAA+ chaperone Rubisco activase (Rca) in a process that is not well understood. Here, we performed a structural and mechanistic analysis of cyanobacterial Rca, a close homolog of plant Rca. In the Rca:Rubisco complex, Rca is positioned over the Rubisco catalytic site under repair and pulls the N-terminal tail of the large Rubisco subunit (RbcL) into the hexamer pore. Simultaneous displacement of the C terminus of the adjacent RbcL opens the catalytic site for inhibitor release. An alternative interaction of Rca with Rubisco is mediated by C-terminal domains that resemble the small Rubisco subunit. These domains, together with the N-terminal AAA+ hexamer, ensure that Rca is packaged with Rubisco into carboxysomes. The cyanobacterial Rca is a dual-purpose protein with functions in Rubisco repair and carboxysome organization.

PubMed: 32979320
DOI: 10.1016/j.cell.2020.09.010

Experimental method

X-RAY DIFFRACTION (1.38 Å)